Ip helper address
I am trying to put a statement on the remote router to allow the clients to obtain an IP address accross the WAN. I have used the ip helper-address command successfully. My problem is that i would like any of the DHCP servers at the central site to be able to service DHCP requests from the remote site. Do I have to use mutilple ip helper-address statements ? I have tried a helper address pointing to the subnet, but that does not seem to work. EX. i have DHCP servers at 10.10.10.10 and 10.10.10.11 do i have to use two seperate ip helper address statements or can i use ip helper-address 10.10.10.0 ? **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associate-Announcement.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
About ip helper-address
I know this is for udp broadcast forward, but is there anyway to forward tcp broadcast? If there is, what scenarios should we use tcp/udp broadcast forward? Thanks ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Ip helper address
You have 2 DHCP servers on the same subnet??? This is probably not a good idea... it does not really provide redundancy or load balancing. The DHCP client will issue a request and accept the first response that it gets. If you split your scope such that half of your available addresses are on one server and half are on the other, you will *NOT* see that half of your clients use one server while half use the other. If for some reason one server always replies a nanosecond earlier than the other, then all clients will accept the response from that server. Once that server is out of addresses, it will start sending nack's. The clients will start accepting those nack's and will not request an address again, even though the other DHCP server may have dozens of free addresses to offer. SO - in answer to your question, the ip helper address of 10.10.10.0 will allow your client's requests to reach all DHCP servers on that subnet, HOWEVER they will only accept leases from the first server from which they receive a response. Chances are that server will be the same one all the time, even after it runs out of addresses to offer... You *could* set up your DHCP servers such that the scope on EACH ONE is sufficient to offer leases to ALL of you clients, but that is probably a less than efficient use of your address space. I hope that this helps... Dale [=`) >From: "Dennis Bates" <[EMAIL PROTECTED]> >Reply-To: "Dennis Bates" <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >Subject: Ip helper address >Date: Fri, 8 Sep 2000 08:10:44 -0500 > >I am trying to put a statement on the remote router to allow the clients to >obtain an IP address accross the WAN. I have used the ip helper-address >command successfully. My problem is that i would like any of the DHCP >servers at the central site to be able to service DHCP requests from the >remote site. Do I have to use mutilple ip helper-address statements ? I >have tried a helper address pointing to the subnet, but that does not seem >to work. EX. i have DHCP servers at 10.10.10.10 and 10.10.10.11 do i have >to >use two seperate ip helper address statements or can i use ip >helper-address >10.10.10.0 ? > > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associate-Announcement.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associate-Announcement.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Ip helper address
what about putting ip helper-address 10.10.10.255 ? instead of a zero.. what effect does that have? isnt the 255 used to send the broadcasts to all the servers on that subnet? jeff -Original Message- From: Dale Holmes [mailto:[EMAIL PROTECTED]] Sent: Fri, September 08, 2000 5:11 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: Re: Ip helper address You have 2 DHCP servers on the same subnet??? This is probably not a good idea... it does not really provide redundancy or load balancing. The DHCP client will issue a request and accept the first response that it gets. If you split your scope such that half of your available addresses are on one server and half are on the other, you will *NOT* see that half of your clients use one server while half use the other. If for some reason one server always replies a nanosecond earlier than the other, then all clients will accept the response from that server. Once that server is out of addresses, it will start sending nack's. The clients will start accepting those nack's and will not request an address again, even though the other DHCP server may have dozens of free addresses to offer. SO - in answer to your question, the ip helper address of 10.10.10.0 will allow your client's requests to reach all DHCP servers on that subnet, HOWEVER they will only accept leases from the first server from which they receive a response. Chances are that server will be the same one all the time, even after it runs out of addresses to offer... You *could* set up your DHCP servers such that the scope on EACH ONE is sufficient to offer leases to ALL of you clients, but that is probably a less than efficient use of your address space. I hope that this helps... Dale [=`) >From: "Dennis Bates" <[EMAIL PROTECTED]> >Reply-To: "Dennis Bates" <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >Subject: Ip helper address >Date: Fri, 8 Sep 2000 08:10:44 -0500 > >I am trying to put a statement on the remote router to allow the clients to >obtain an IP address accross the WAN. I have used the ip helper-address >command successfully. My problem is that i would like any of the DHCP >servers at the central site to be able to service DHCP requests from the >remote site. Do I have to use mutilple ip helper-address statements ? I >have tried a helper address pointing to the subnet, but that does not seem >to work. EX. i have DHCP servers at 10.10.10.10 and 10.10.10.11 do i have >to >use two seperate ip helper address statements or can i use ip >helper-address >10.10.10.0 ? > > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associate-Announcement.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associate-Announcement.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Ip helper address
I don't understand this, wouldn't the client accept the second offer by sending the seconds servers siaddr in the request packet. also DHCP standard says that nowhere must a client accept the first offer and then stop broadcasting. All servers will answer the clients DHCPDISCOVER broadcast with any help it can or can not offer. The first server does not tell the second server to shutup so as soon as the (second or 1nanosecond slower server) receives the broadcast it will it will send a DHCPOFFER packet and the client will reply with an DHCPREQUEST packet to the second server (using the siaddr field) that will be ack'd by the second server with an DHCPACK packet. This is all made quite clear in RFC 1541. So you can have two DHCP servers on the same segment you just don't know which one will serve the address to the client but both will try independent of each other and the client will ot stop trying after receiving after a nack from a server. Duck - Original Message - From: Dale Holmes <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Friday, September 08, 2000 7:10 AM Subject: Re: Ip helper address > > You have 2 DHCP servers on the same subnet??? This is probably not a good > idea... it does not really provide redundancy or load balancing. > The DHCP client will issue a request and accept the first response that it > gets. > > If you split your scope such that half of your available addresses are on > one server and half are on the other, you will *NOT* see that half of your > clients use one server while half use the other. If for some reason one > server always replies a nanosecond earlier than the other, then all clients > will accept the response from that server. Once that server is out of > addresses, it will start sending nack's. The clients will start accepting > those nack's and will not request an address again, even though the other > DHCP server may have dozens of free addresses to offer. > > SO - in answer to your question, the ip helper address of 10.10.10.0 will > allow your client's requests to reach all DHCP servers on that subnet, > HOWEVER they will only accept leases from the first server from which they > receive a response. Chances are that server will be the same one all the > time, even after it runs out of addresses to offer... > > You *could* set up your DHCP servers such that the scope on EACH ONE is > sufficient to offer leases to ALL of you clients, but that is probably a > less than efficient use of your address space. > > I hope that this helps... > > Dale > [=`) > > >From: "Dennis Bates" <[EMAIL PROTECTED]> > >Reply-To: "Dennis Bates" <[EMAIL PROTECTED]> > >To: [EMAIL PROTECTED] > >Subject: Ip helper address > >Date: Fri, 8 Sep 2000 08:10:44 -0500 > > > >I am trying to put a statement on the remote router to allow the clients to > >obtain an IP address accross the WAN. I have used the ip helper-address > >command successfully. My problem is that i would like any of the DHCP > >servers at the central site to be able to service DHCP requests from the > >remote site. Do I have to use mutilple ip helper-address statements ? I > >have tried a helper address pointing to the subnet, but that does not seem > >to work. EX. i have DHCP servers at 10.10.10.10 and 10.10.10.11 do i have > >to > >use two seperate ip helper address statements or can i use ip > >helper-address > >10.10.10.0 ? > > > > > >**NOTE: New CCNA/CCDA List has been formed. For more information go to > >http://www.groupstudy.com/list/Associate-Announcement.html > >_ > >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > >FAQ, list archives, and subscription info: http://www.groupstudy.com > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > **NOTE: New CCNA/CCDA List has been formed. For more information go to > http://www.groupstudy.com/list/Associate-Announcement.html > _ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Ip helper address
Perhaps I should be more clear about this and say that this is the behaviour of MICROSOFT DHCP clients. Here is the info from the Windows NT Resource kit: "Note: The client accepts the first offer it receives, regardless of whether the offer came from a DHCP server on the local subnet or from a DHCP server on a different subnet. ... In the case where the DHCP server is unavailable or there is no available IP addressing information to lease to a client computer, the client is unable to bind to TCP/IP." An MS DHCP client may receive many DHCPOFFER's for its DHCPDISCOVER broadcast. It will accept the first offer it receives (actually, the first response it gets), and NACK all others. If the first response it gets is negative, it will settle for that, and NACK anything from the other servers. I have seen this (and sniffer traced it) in production. MS was unwilling to call it a bug, and said the behaviour was by design and was RFC compliant. Case was closed... This was NT 4.0 Service pack 4 with Win98 clients. I dunno if they have changed things since, but I doubt it. Dale [=`) >From: "Donald B Johnson Jr" <[EMAIL PROTECTED]> >To: "Dale Holmes" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>, ><[EMAIL PROTECTED]> >Subject: Re: Ip helper address >Date: Mon, 11 Sep 2000 12:36:49 -0700 > >I don't understand this, wouldn't the client accept the second offer by >sending the seconds servers siaddr in the request packet. also DHCP >standard >says that nowhere must a client accept the first offer and then stop >broadcasting. All servers will answer the clients DHCPDISCOVER broadcast >with any help it can or can not offer. The first server does not tell the >second server to shutup so as soon as the (second or 1nanosecond slower >server) receives the broadcast it will it will send a DHCPOFFER packet and >the client will reply with an DHCPREQUEST packet to the second server >(using the siaddr field) that will be ack'd by the second server with an >DHCPACK packet. This is all made quite clear in RFC 1541. So you can have >two DHCP servers on the same segment you just don't know which one will >serve the address to the client but both will try independent of each other >and the client will ot stop trying after receiving after a nack from a >server. >Duck >- Original Message ----- >From: Dale Holmes <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> >Sent: Friday, September 08, 2000 7:10 AM >Subject: Re: Ip helper address > > > > > > You have 2 DHCP servers on the same subnet??? This is probably not a >good > > idea... it does not really provide redundancy or load balancing. > > The DHCP client will issue a request and accept the first response that >it > > gets. > > > > If you split your scope such that half of your available addresses are >on > > one server and half are on the other, you will *NOT* see that half of >your > > clients use one server while half use the other. If for some reason one > > server always replies a nanosecond earlier than the other, then all >clients > > will accept the response from that server. Once that server is out of > > addresses, it will start sending nack's. The clients will start >accepting > > those nack's and will not request an address again, even though the >other > > DHCP server may have dozens of free addresses to offer. > > > > SO - in answer to your question, the ip helper address of 10.10.10.0 >will > > allow your client's requests to reach all DHCP servers on that subnet, > > HOWEVER they will only accept leases from the first server from which >they > > receive a response. Chances are that server will be the same one all the > > time, even after it runs out of addresses to offer... > > > > You *could* set up your DHCP servers such that the scope on EACH ONE is > > sufficient to offer leases to ALL of you clients, but that is probably a > > less than efficient use of your address space. > > > > I hope that this helps... > > > > Dale > > [=`) > > > > >From: "Dennis Bates" <[EMAIL PROTECTED]> > > >Reply-To: "Dennis Bates" <[EMAIL PROTECTED]> > > >To: [EMAIL PROTECTED] > > >Subject: Ip helper address > > >Date: Fri, 8 Sep 2000 08:10:44 -0500 > > > > > >I am trying to put a statement on the remote router to allow the >clients >to > > >obtain an IP address accross the WAN. I have used the ip >helper-address > > >command successfully. My problem is that i would like any of the DHCP > > >servers at the cen
Re: Ip helper address
It is possible two have two DHCP servers in one subnet. The client will
accept the first IP address it recieves. This is done to remove the Single
point-of-failure in the one DHCP server. Some DHCP server software will
allow two or more servers to share a synchronized copy of the address pool
database, to simplify administration.
Getting to the question...
According to the Cisco Press ACRC book, if you have multiple ip
helper-address ('S) defined, any UDP broadcasts recieved on the allowed udp
ports will be unicasted to each of the IP helpers.
It's not just DHCP either, it's:
DHCP, DNS, TFTP, TIME, NETBIOS NAME SERVICE, NETBIOS DATAGRAM SERVICE, AND
TACACS.
Original Message Follows
From: "Donald B Johnson Jr" <[EMAIL PROTECTED]>
Reply-To: "Donald B Johnson Jr" <[EMAIL PROTECTED]>
To: "Dale Holmes" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>,
<[EMAIL PROTECTED]>
Subject: Re: Ip helper address
Date: Mon, 11 Sep 2000 12:36:49 -0700
I don't understand this, wouldn't the client accept the second offer by
sending the seconds servers siaddr in the request packet. also DHCP standard
says that nowhere must a client accept the first offer and then stop
broadcasting. All servers will answer the clients DHCPDISCOVER broadcast
with any help it can or can not offer. The first server does not tell the
second server to shutup so as soon as the (second or 1nanosecond slower
server) receives the broadcast it will it will send a DHCPOFFER packet and
the client will reply with an DHCPREQUEST packet to the second server
(using the siaddr field) that will be ack'd by the second server with an
DHCPACK packet. This is all made quite clear in RFC 1541. So you can have
two DHCP servers on the same segment you just don't know which one will
serve the address to the client but both will try independent of each other
and the client will ot stop trying after receiving after a nack from a
server.
Duck
- Original Message -
From: Dale Holmes <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Friday, September 08, 2000 7:10 AM
Subject: Re: Ip helper address
>
> You have 2 DHCP servers on the same subnet??? This is probably not a good
> idea... it does not really provide redundancy or load balancing.
> The DHCP client will issue a request and accept the first response that
it
> gets.
>
> If you split your scope such that half of your available addresses are on
> one server and half are on the other, you will *NOT* see that half of
your
> clients use one server while half use the other. If for some reason one
> server always replies a nanosecond earlier than the other, then all
clients
> will accept the response from that server. Once that server is out of
> addresses, it will start sending nack's. The clients will start accepting
> those nack's and will not request an address again, even though the other
> DHCP server may have dozens of free addresses to offer.
>
> SO - in answer to your question, the ip helper address of 10.10.10.0 will
> allow your client's requests to reach all DHCP servers on that subnet,
> HOWEVER they will only accept leases from the first server from which
they
> receive a response. Chances are that server will be the same one all the
> time, even after it runs out of addresses to offer...
>
> You *could* set up your DHCP servers such that the scope on EACH ONE is
> sufficient to offer leases to ALL of you clients, but that is probably a
> less than efficient use of your address space.
>
> I hope that this helps...
>
> Dale
> [=`)
>
> >From: "Dennis Bates" <[EMAIL PROTECTED]>
> >Reply-To: "Dennis Bates" <[EMAIL PROTECTED]>
> >To: [EMAIL PROTECTED]
> >Subject: Ip helper address
> >Date: Fri, 8 Sep 2000 08:10:44 -0500
> >
> >I am trying to put a statement on the remote router to allow the clients
to
> >obtain an IP address accross the WAN. I have used the ip helper-address
> >command successfully. My problem is that i would like any of the DHCP
> >servers at the central site to be able to service DHCP requests from the
> >remote site. Do I have to use mutilple ip helper-address statements ?
I
> >have tried a helper address pointing to the subnet, but that does not
seem
> >to work. EX. i have DHCP servers at 10.10.10.10 and 10.10.10.11 do i
have
> >to
> >use two seperate ip helper address statements or can i use ip
> >helper-address
> >10.10.10.0 ?
> >
> >
> >**NOTE: New CCNA/CCDA List has been formed. For more information go to
> >http://www.groupstudy.com/list/Associate-Announcement.html
> >__
Re: Ip helper address
Doesn't a MS client go for a new server after 87.5% of the lease if It can't contact it's original server. I got a resource kit collecting dust somewhere what page is that on I'd like to look that up microsoft always seems to amaze me with there bugs. Maybe you should e-mail them the RFC. If you got a print out for the sniff I'd like to take a look at that too. Duck - Original Message - From: Dale Holmes <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Monday, September 11, 2000 10:10 AM Subject: Re: Ip helper address > Perhaps I should be more clear about this and say that this is the behaviour > of MICROSOFT DHCP clients. Here is the info from the Windows NT Resource > kit: > > "Note: The client accepts the first offer it receives, regardless of > whether the offer came from a DHCP server on the local subnet or from a DHCP > server on a different subnet. ... In the case where the DHCP server is > unavailable or there is no available IP addressing information to lease to a > client computer, the client is unable to bind to TCP/IP." > > An MS DHCP client may receive many DHCPOFFER's for its DHCPDISCOVER > broadcast. It will accept the first offer it receives (actually, the first > response it gets), and NACK all others. If the first response it gets is > negative, it will settle for that, and NACK anything from the other servers. > I have seen this (and sniffer traced it) in production. MS was unwilling to > call it a bug, and said the behaviour was by design and was RFC compliant. > Case was closed... > > This was NT 4.0 Service pack 4 with Win98 clients. I dunno if they have > changed things since, but I doubt it. > > Dale > [=`) > > > > > >From: "Donald B Johnson Jr" <[EMAIL PROTECTED]> > >To: "Dale Holmes" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>, > ><[EMAIL PROTECTED]> > >Subject: Re: Ip helper address > >Date: Mon, 11 Sep 2000 12:36:49 -0700 > > > >I don't understand this, wouldn't the client accept the second offer by > >sending the seconds servers siaddr in the request packet. also DHCP > >standard > >says that nowhere must a client accept the first offer and then stop > >broadcasting. All servers will answer the clients DHCPDISCOVER broadcast > >with any help it can or can not offer. The first server does not tell the > >second server to shutup so as soon as the (second or 1nanosecond slower > >server) receives the broadcast it will it will send a DHCPOFFER packet and > >the client will reply with an DHCPREQUEST packet to the second server > >(using the siaddr field) that will be ack'd by the second server with an > >DHCPACK packet. This is all made quite clear in RFC 1541. So you can have > >two DHCP servers on the same segment you just don't know which one will > >serve the address to the client but both will try independent of each other > >and the client will ot stop trying after receiving after a nack from a > >server. > >Duck > >- Original Message - > >From: Dale Holmes <[EMAIL PROTECTED]> > >To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> > >Sent: Friday, September 08, 2000 7:10 AM > >Subject: Re: Ip helper address > > > > > > > > > > You have 2 DHCP servers on the same subnet??? This is probably not a > >good > > > idea... it does not really provide redundancy or load balancing. > > > The DHCP client will issue a request and accept the first response that > >it > > > gets. > > > > > > If you split your scope such that half of your available addresses are > >on > > > one server and half are on the other, you will *NOT* see that half of > >your > > > clients use one server while half use the other. If for some reason one > > > server always replies a nanosecond earlier than the other, then all > >clients > > > will accept the response from that server. Once that server is out of > > > addresses, it will start sending nack's. The clients will start > >accepting > > > those nack's and will not request an address again, even though the > >other > > > DHCP server may have dozens of free addresses to offer. > > > > > > SO - in answer to your question, the ip helper address of 10.10.10.0 > >will > > > allow your client's requests to reach all DHCP servers on that subnet, > > > HOWEVER they will only accept leases from the first server from which > >they > > > receive a response. Chances are that server wi
help with IP Helper Address
A couple years ago we (actually my predecessor) removed a server from a small remote stub network (172.26.91.X). All the printers were moved to a print server on the main network (172.26.90.X) and kept their assigned ip's in network 172.26.91.X. The two networks are connected via a 4000 series on the 90.X end and a 2500 series on the 91.X end. When a user in network 91.X tries to map a printer, none show up in the box (WinNT). I can't reasonably expect all of them to all remember the UNC names for their printers. I started searching CCO for a solution and it seems to be "IP Helper Address" I have noticed that I don't have any set and always wondered what they were, well, now I know. The question is, on which router do I put the address of the print server?? Thanks Tim _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
IP Helper Address [7:13539]
I have heard this term "IP helper address" used to reference a default gateway. Is an IP helper address the same as a default gateway? If not what is an IP helper address? Do you know where the term came from? Jason Kinney 925-961-0223 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13539&t=13539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: About ip helper-address
>I know this is for udp broadcast forward, but is there anyway to forward tcp >broadcast? If there is, what scenarios should we use tcp/udp broadcast >forward? >Thanks > > What have you seen that produces TCP broadcasts? As a study question, why would it be unlikely to have a broadcast mechanism based on TCP? ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: About ip helper-address
Actually, that was my questions too. I am not sure if all broadcast are based on udp instead of TCP, like all multicast are based on udp to avoice unnecessary retransmission. Maybe broadcast is the same case. Is my understanding correct? Cisco has a "ip forward-protocol dns", is it true that it is designed for diskless workstation, say the DNS server ip add is not configured and need broadcast dns query request? I think normally DNS ip address is already pre-configured, so the DNS query should be a unicast instead of broadcast. ""Howard C. Berkowitz"" <[EMAIL PROTECTED]> wrote in message news:v04220870b5ceea79b3db@[63.216.127.98]... > >I know this is for udp broadcast forward, but is there anyway to forward tcp > >broadcast? If there is, what scenarios should we use tcp/udp broadcast > >forward? > >Thanks > > > > > What have you seen that produces TCP broadcasts? > > As a study question, why would it be unlikely to have a broadcast > mechanism based on TCP? > > ___ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: About ip helper-address
I dont see any point in using broadcasts with TCP cuz u have a TCP connection between two devices only .. -Original Message- From: Sean Wu <[EMAIL PROTECTED]> Newsgroups: groupstudy.cisco To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Sunday, August 27, 2000 10:10 PM Subject: Re: About ip helper-address >Actually, that was my questions too. I am not sure if all broadcast are >based on udp instead of TCP, like all multicast are based on udp to avoice >unnecessary retransmission. Maybe broadcast is the same case. Is my >understanding correct? > >Cisco has a "ip forward-protocol dns", is it true that it is designed for >diskless workstation, say the DNS server ip add is not configured and need >broadcast dns query request? I think normally DNS ip address is already >pre-configured, so the DNS query should be a unicast instead of broadcast. > > > >""Howard C. Berkowitz"" <[EMAIL PROTECTED]> wrote in message >news:v04220870b5ceea79b3db@[63.216.127.98]... >> >I know this is for udp broadcast forward, but is there anyway to forward >tcp >> >broadcast? If there is, what scenarios should we use tcp/udp broadcast >> >forward? >> >Thanks >> > >> > >> What have you seen that produces TCP broadcasts? >> >> As a study question, why would it be unlikely to have a broadcast >> mechanism based on TCP? >> >> ___ >> UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >> FAQ, list archives, and subscription info: http://www.groupstudy.com >> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] >> > >___ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: About ip helper-address
i'll take a stab at howard's question: because of the reliability requirements placed by tcp ? -Original Message- From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] Sent: Sunday, August 27, 2000 11:56 AM To: [EMAIL PROTECTED] Subject: Re: About ip helper-address >I know this is for udp broadcast forward, but is there anyway to forward tcp >broadcast? If there is, what scenarios should we use tcp/udp broadcast >forward? >Thanks > > What have you seen that produces TCP broadcasts? As a study question, why would it be unlikely to have a broadcast mechanism based on TCP? ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: About ip helper-address
>i'll take a stab at howard's question: > >because of the reliability requirements placed by tcp ? You're on the right track. What relationships and topologies do these requirements suggest between sender and receiver? > >-Original Message- >From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] >Sent: Sunday, August 27, 2000 11:56 AM > > > >I know this is for udp broadcast forward, but is there anyway to forward >tcp > >broadcast? If there is, what scenarios should we use tcp/udp broadcast > >forward? > >Thanks > > > > >What have you seen that produces TCP broadcasts? > >As a study question, why would it be unlikely to have a broadcast >mechanism based on TCP? ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: About ip helper-address
On Sun, Aug 27, 2000 at 01:04:52PM -0400 or thereabouts, Sean Wu wrote: > Actually, that was my questions too. I am not sure if all broadcast are > based on udp instead of TCP, like all multicast are based on udp to avoice > unnecessary retransmission. Maybe broadcast is the same case. Is my > understanding correct? Broadcasts are connectionless, which classifies them as UDP. > Cisco has a "ip forward-protocol dns", is it true that it is designed for > diskless workstation, say the DNS server ip add is not configured and need > broadcast dns query request? I think normally DNS ip address is already > pre-configured, so the DNS query should be a unicast instead of broadcast. If you have an ip helper-address defined, then essentially, the forward-protocol is defined by default, as all broadcasts that come in that interface will be sent to that address. This means any dhcp, tftp, dns, netbios, etc broadcasts will be sent to the helper-address defined. That can end up being quite an amount of traffic depending upon the size of your network. The forward-protocol will also allow you to specify which protocols you do not want forwarded: no ip forward-protocol udp netbios-ns (port 137, netbios name service) This will cut down on any unnecessary/unwanted traffic going out to the specified helper-address. Also, keep in mind when configuring what will be forwarded and what will not be, that the ip helper-address is assigned to the interface, but the forward-protocol is a global configuration command. Hope this helps, Erica --- Erica L Johansson Network Engineer Cablevision Systems Corporation --- ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: About ip helper-address
syn, syn-ack and ack anytime i see tcp i think of a one-to-one communication that must adhere to the 3-way handshake. -Original Message- From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] Sent: Sunday, August 27, 2000 1:49 PM To: [EMAIL PROTECTED] Subject: RE: About ip helper-address >i'll take a stab at howard's question: > >because of the reliability requirements placed by tcp ? You're on the right track. What relationships and topologies do these requirements suggest between sender and receiver? > >-Original Message- >From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] >Sent: Sunday, August 27, 2000 11:56 AM > > > >I know this is for udp broadcast forward, but is there anyway to forward >tcp > >broadcast? If there is, what scenarios should we use tcp/udp broadcast > >forward? > >Thanks > > > > >What have you seen that produces TCP broadcasts? > >As a study question, why would it be unlikely to have a broadcast >mechanism based on TCP? ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: About ip helper-address
>syn, syn-ack and ack > >anytime i see tcp i think of a one-to-one communication that must adhere to >the 3-way handshake. Right. There are several good reasons to use broadcast/multicast (as distinct from simply being connectionless): 1. You don't know the address of the destination (e.g., DHCP request) 2. The nature of the application is one-to-many and doesn't need reliable transmission (e.g., television broadcasting) 3. The transmitter can resend information "in the blind" a sufficient number of times that there is an acceptable statistical likelihood that the receiver will receive a copy (e.g., weather map broadcasts) There certainly are applications where reliable multicast services would be very useful, but general purpose reliable multicast remains a research problem. Reliable multicast protocols do exist for certain applications, and it's not surprising that the details of its reliable multicast are the "family jewels" of EIGRP and have not been made public. > >-Original Message- >From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] >Sent: Sunday, August 27, 2000 1:49 PM >To: [EMAIL PROTECTED] >Subject: RE: About ip helper-address > > > >i'll take a stab at howard's question: > > > >because of the reliability requirements placed by tcp ? > > >You're on the right track. What relationships and topologies do >these requirements suggest between sender and receiver? > > > > >-Original Message- > >From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]] > >Sent: Sunday, August 27, 2000 11:56 AM > > > > > > >I know this is for udp broadcast forward, but is there anyway to forward > >tcp > > >broadcast? If there is, what scenarios should we use tcp/udp broadcast > > >forward? > > >Thanks > > > > > > > >What have you seen that produces TCP broadcasts? > > > >As a study question, why would it be unlikely to have a broadcast > >mechanism based on TCP? ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
ip helper address [7:45042]
Can you put more than one ip helper address on an ethernet interface? If so, what is the syntax to do so? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=45042&t=45042 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
ip helper address [7:73533]
Assume that you have a two routers between your host and dhcp server. This means that you have a 4 interfaces you cna put "ip helper-address" on. On which interface(s) you will put the above command. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73533&t=73533 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: help with IP Helper Address
Put it on the router nearest the person who needs access to the remote resources. >From: "Timothy Metz" <[EMAIL PROTECTED]> >Reply-To: "Timothy Metz" <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >Subject: help with IP Helper Address >Date: Tue, 28 Nov 2000 18:25:28 +0100 > >A couple years ago we (actually my predecessor) removed a server from a >small remote stub network (172.26.91.X). All the printers were moved to a >print server on the main network (172.26.90.X) and kept their assigned ip's >in network 172.26.91.X. The two networks are connected via a 4000 series on >the 90.X end and a 2500 series on the 91.X end. When a user in network 91.X >tries to map a printer, none show up in the box (WinNT). I can't reasonably >expect all of them to all remember the UNC names for their printers. I >started searching CCO for a solution and it seems to be "IP Helper Address" >I have noticed that I don't have any set and always wondered what they >were, >well, now I know. The question is, on which router do I put the address of >the print server?? > >Thanks > >Tim > > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: help with IP Helper Address
Great, thanks! Tim ""Frank Wells"" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Put it on the router nearest the person who needs access to the remote > resources. > > > >From: "Timothy Metz" <[EMAIL PROTECTED]> > >Reply-To: "Timothy Metz" <[EMAIL PROTECTED]> > >To: [EMAIL PROTECTED] > >Subject: help with IP Helper Address > >Date: Tue, 28 Nov 2000 18:25:28 +0100 > > > >A couple years ago we (actually my predecessor) removed a server from a > >small remote stub network (172.26.91.X). All the printers were moved to a > >print server on the main network (172.26.90.X) and kept their assigned ip's > >in network 172.26.91.X. The two networks are connected via a 4000 series on > >the 90.X end and a 2500 series on the 91.X end. When a user in network 91.X > >tries to map a printer, none show up in the box (WinNT). I can't reasonably > >expect all of them to all remember the UNC names for their printers. I > >started searching CCO for a solution and it seems to be "IP Helper Address" > >I have noticed that I don't have any set and always wondered what they > >were, > >well, now I know. The question is, on which router do I put the address of > >the print server?? > > > >Thanks > > > >Tim > > > > > >_ > >FAQ, list archives, and subscription info: > >http://www.groupstudy.com/list/cisco.html > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > _ > Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: help with IP Helper Address
IP helper address is forwarding all the NON-routable protocols and Broadcasts to a NT server (direct IP address after the command) or to a subnet (e.g. Ip helper-address 172.26.90.255) The command must be put on the Ethernet interface of the 25xx. Hope this help. Regards Elias Aggelidis ALGOSYSTEMS SA Network Engineer 4, Sardeon Str CCNA, CCNPNea Smyrni CVOICE Specialised PICA Administrator Athens 17121 tel: +301-9310281 GREECE fax: +301-9352873 email: [EMAIL PROTECTED] BEGIN:VCARD VERSION:2.1 N:Aggelidis;Elias FN:Elias Aggelidis NICKNAME:ilias ORG:Algosystems S.A;Technical Assistance Center TITLE:Network Engineer - CCNA, CCNP TEL;WORK;VOICE:+30-1-9310281 TEL;HOME;VOICE:+30-1-2521495 TEL;CELL;VOICE:+30-93-7329117 TEL;WORK;FAX:+30-1-9352873 ADR;WORK:;218;4, Sardeon st.;Nea Smyrni;Athens;171-21;Greece LABEL;WORK;ENCODING=QUOTED-PRINTABLE:218=0D=0A4, Sardeon st.=0D=0ANea Smyrni, Athens 171-21=0D=0AGreece X-WAB-GENDER:2 URL: URL:http://www.algo.com.gr BDAY:19720422 EMAIL;PREF;INTERNET:[EMAIL PROTECTED] REV:20001129T090953Z END:VCARD
IP Helper-address questions [7:247]
I have two routers connected via serial point to point link. Router 1 has an ethernet segment with PDC info I want forwarded to Router 2 ethernet segment. No ip directed broadcast is configured on all interfaces. I want netbios traffic passed from one segment to the other. I have placed an IP helper-address statement on the ethernet interface needing the help. Do I need to use the ip helper-address on all interfaces to the source ip helper-address? Is the ip forward-protocol also necessary? Any advice would be greatly appreciated David Eitel Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=247&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP Helper Address [7:13539]
An Ip helper address allows you to propagate (repeat) certain types of broadcasts across the wan to one or more remote machines. Two example of things that are useful with helper addresses are DHCP, Win9x NETBios Browsing w/o wins. -Original Message- From: Jason Kinney [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 24, 2001 12:52 PM To: [EMAIL PROTECTED] Subject: IP Helper Address [7:13539] I have heard this term "IP helper address" used to reference a default gateway. Is an IP helper address the same as a default gateway? If not what is an IP helper address? Do you know where the term came from? Jason Kinney 925-961-0223 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13550&t=13539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper Address [7:13539]
no...the two are nothing alike a default gateway is just thatyour next hop out. and ip helper can be any address on any subnet that would generally answer a broadcast from a host on a local segment. But since routers stop broadcasts by default, you must specify this address as a "helper" . The router then takes would would normally be a broadcast and forwards it to this "helper" address as a unicast. (most commonly used in this scenario is bootp/dhcp) -Patrick >>> "Jason Kinney" 07/24/01 12:52PM >>> I have heard this term "IP helper address" used to reference a default gateway. Is an IP helper address the same as a default gateway? If not what is an IP helper address? Do you know where the term came from? Jason Kinney 925-961-0223 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13554&t=13539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper Address [7:13539]
ip helper address can be used to find a dhcp server on a different segment than what you are. Your computer will broadcast a dhcp request (layer 3 which will not get through a router) for a dhcp server on a different segment. ip helper address will allow your machine access to the dhcp server through the router. however, be aware that ip helper address does open up other ports. - Original Message - From: Jason Kinney To: Sent: Tuesday, July 24, 2001 11:52 AM Subject: IP Helper Address [7:13539] > I have heard this term "IP helper address" used to reference a default > gateway. Is an IP helper address the same as a default gateway? If not > what is an IP helper address? Do you know where the term came from? > > Jason Kinney > 925-961-0223 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=13558&t=13539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ip helper address [7:45042]
Yes you can. Just type in the command multiple times in the interface config mode. If servers are on the same network, then you can use the network address instead of the host addr. For example: servers are 1.1.1.1 and 1.1.1.2/24 then: r1(config-if)#ip helper-addres 1.1.1.1 r1(config-if)#ip helper-addres 1.1.1.2 or r1(config-if)#ip helper-addres 1.1.1.0 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Saturday, May 25, 2002 12:59 PM To: [EMAIL PROTECTED] Subject: ip helper address [7:45042] Can you put more than one ip helper address on an ethernet interface? If so, what is the syntax to do so? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=45043&t=45042 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ip helper address [7:73533]
The one closest to the host. Thanks, Zsombor Janik James wrote: > > Assume that you have a two routers between your host and dhcp > server. > This means that you have a 4 interfaces you cna put "ip > helper-address" on. On which interface(s) you will put the > above command. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73534&t=73533 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: ip helper address [7:73533]
Bah! Good try, but you can't use the greater than or less than characters in this list. Bit me the first time also... Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Creighton, Bill [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 2:33 PM To: [EMAIL PROTECTED] Subject: RE: ip helper address [7:73533] the interface closest to the host Host -Server (DHCP) In the example above the address would be applied to interface E0 of Router A Bill Creighton CCNP Network Design Engineer, eVPN AT&T Business Service Delivery NSPM > -Original Message- > From: Janik James [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 10:35 AM > To: [EMAIL PROTECTED] > Subject: ip helper address [7:73533] > > > Assume that you have a two routers between your host and dhcp server. > This means that you have a 4 interfaces you cna put "ip > helper-address" on. > On which interface(s) you will put the above command. > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73560&t=73533 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: ip helper address [7:73533]
the interface closest to the host Host -Server (DHCP) In the example above the address would be applied to interface E0 of Router A Bill Creighton CCNP Network Design Engineer, eVPN AT&T Business Service Delivery NSPM > -Original Message- > From: Janik James [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 10:35 AM > To: [EMAIL PROTECTED] > Subject: ip helper address [7:73533] > > > Assume that you have a two routers between your host and dhcp server. > This means that you have a 4 interfaces you cna put "ip > helper-address" on. > On which interface(s) you will put the above command. > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73549&t=73533 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: ip helper address [7:73533]
/it always has to go on the router int closest to the host. -Original Message- From: Janik James [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 11:35 AM To: [EMAIL PROTECTED] Subject: ip helper address [7:73533] Assume that you have a two routers between your host and dhcp server. This means that you have a 4 interfaces you cna put "ip helper-address" on. On which interface(s) you will put the above command. **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73541&t=73533 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: IP Helper-address questions [7:247]
I assume when you say PDC, you are referring to an NT server PDC. I must also assume you have TCP/IP installed on all NT servers needing to communicate to each other. If so, then the ip-helper command is of no use. It merely forwards bootp and DHCP requests. If you need a PDC and a BDC to communicate then just make sure both servers are reporting to a common WINS server. From the WINS server the PDC and BDC will know what IP addresses they nees to use to communicate. As long as the servers can ping each other and WINS is configured properly then you are cooking. Thanks, Patrick -Original Message- From: David Eitel To: [EMAIL PROTECTED] Sent: 4/11/2001 2:45 PM Subject: IP Helper-address questions [7:247] I have two routers connected via serial point to point link. Router 1 has an ethernet segment with PDC info I want forwarded to Router 2 ethernet segment. No ip directed broadcast is configured on all interfaces. I want netbios traffic passed from one segment to the other. I have placed an IP helper-address statement on the ethernet interface needing the help. Do I need to use the ip helper-address on all interfaces to the source ip helper-address? Is the ip forward-protocol also necessary? Any advice would be greatly appreciated David Eitel FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=263&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
Actually, the IP helper command is placed on the interface that is recieving the broadcasts. Now you have to decide which router is supposed to recieve the broadcasts. But in usual case, Clients usually try to communcate with the PDC for authentication and other stuffs. So, i think it would work to configure ip helper-address w.x.y.z on the ethernet interface of router 1 only (where w.x.y.z is the ip address of your PDC, but if you have multiple PDCs then you have to give the directed-broadcast address and also have to use ip directed-broadcast command). I hope this will work Muhammad Khalilullah CCNP, MCSE --- David Eitel wrote: > I have two routers connected via serial point to > point link. Router 1 has > an ethernet segment with PDC info I want forwarded > to Router 2 ethernet > segment. No ip directed broadcast is configured on > all interfaces. I want > netbios traffic passed from one segment to the > other. I have placed an IP > helper-address statement on the ethernet interface > needing the help. Do I > need to use the ip helper-address on all interfaces > to the source ip > helper-address? Is the ip forward-protocol also > necessary? Any advice would > be greatly appreciated > > David Eitel > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=313&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
Here's a fun link explaining ip helper: http://routergod.com/trinity/ -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ ""Muhammed Khalilullah"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Actually, the IP helper command is placed on the > interface that is recieving the broadcasts. Now you > have to decide which router is supposed to recieve the > broadcasts. But in usual case, Clients usually try to > communcate with the PDC for authentication and other > stuffs. So, i think it would work to configure ip > helper-address w.x.y.z on the ethernet interface of > router 1 only (where w.x.y.z is the ip address of your > PDC, but if you have multiple PDCs then you have to > give the directed-broadcast address and also have to > use ip directed-broadcast command). > > I hope this will work > > Muhammad Khalilullah > CCNP, MCSE > > --- David Eitel wrote: > > I have two routers connected via serial point to > > point link. Router 1 has > > an ethernet segment with PDC info I want forwarded > > to Router 2 ethernet > > segment. No ip directed broadcast is configured on > > all interfaces. I want > > netbios traffic passed from one segment to the > > other. I have placed an IP > > helper-address statement on the ethernet interface > > needing the help. Do I > > need to use the ip helper-address on all interfaces > > to the source ip > > helper-address? Is the ip forward-protocol also > > necessary? Any advice would > > be greatly appreciated > > > > David Eitel > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to > [EMAIL PROTECTED] > > > __ > Do You Yahoo!? > Get email at your own domain with Yahoo! Mail. > http://personal.mail.yahoo.com/ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=563&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
I happen to be a ccnp and mcse. I get how ip helper-address works. Also work with microsoft dhcp servers. How do you setup a scope for a remote subnet, and how does the dhcp server know how to hand out the correct ip leases for a non-connected subnet? Does the dhcp server look at the source address of the interface of the forwarded helper-address packets? Then match up the correct scope with the router interface ip address? ""Jason J. Roysdon"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Here's a fun link explaining ip helper: > http://routergod.com/trinity/ > > -- > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ > List email: [EMAIL PROTECTED] > Homepage: http://jason.artoo.net/ > > > > ""Muhammed Khalilullah"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Actually, the IP helper command is placed on the > > interface that is recieving the broadcasts. Now you > > have to decide which router is supposed to recieve the > > broadcasts. But in usual case, Clients usually try to > > communcate with the PDC for authentication and other > > stuffs. So, i think it would work to configure ip > > helper-address w.x.y.z on the ethernet interface of > > router 1 only (where w.x.y.z is the ip address of your > > PDC, but if you have multiple PDCs then you have to > > give the directed-broadcast address and also have to > > use ip directed-broadcast command). > > > > I hope this will work > > > > Muhammad Khalilullah > > CCNP, MCSE > > > > --- David Eitel wrote: > > > I have two routers connected via serial point to > > > point link. Router 1 has > > > an ethernet segment with PDC info I want forwarded > > > to Router 2 ethernet > > > segment. No ip directed broadcast is configured on > > > all interfaces. I want > > > netbios traffic passed from one segment to the > > > other. I have placed an IP > > > helper-address statement on the ethernet interface > > > needing the help. Do I > > > need to use the ip helper-address on all interfaces > > > to the source ip > > > helper-address? Is the ip forward-protocol also > > > necessary? Any advice would > > > be greatly appreciated > > > > > > David Eitel > > > FAQ, list archives, and subscription info: > > > http://www.groupstudy.com/list/cisco.html > > > Report misconduct and Nondisclosure violations to > > [EMAIL PROTECTED] > > > > > > __ > > Do You Yahoo!? > > Get email at your own domain with Yahoo! Mail. > > http://personal.mail.yahoo.com/ > > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=720&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
Yup, you got it. Just set up the extra scope(s) for the subnet(s) you have the ip helper-address enabled port(s) on. The DHCP server sees the source address (or perhaps network address/mask, I'm not sure the down and dirty details), and sends an appropriate DHCP address from the scope that fits that subnet. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ ""Michael Snyder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I happen to be a ccnp and mcse. I get how ip helper-address works. Also > work with microsoft dhcp servers. > > How do you setup a scope for a remote subnet, and how does the dhcp server > know how to hand out the correct ip leases for a non-connected subnet? > > Does the dhcp server look at the source address of the interface of the > forwarded helper-address packets? Then match up the correct scope with the > router interface ip address? > > > > > ""Jason J. Roysdon"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Here's a fun link explaining ip helper: > > http://routergod.com/trinity/ > > > > -- > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ > > List email: [EMAIL PROTECTED] > > Homepage: http://jason.artoo.net/ > > > > > > > > ""Muhammed Khalilullah"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Actually, the IP helper command is placed on the > > > interface that is recieving the broadcasts. Now you > > > have to decide which router is supposed to recieve the > > > broadcasts. But in usual case, Clients usually try to > > > communcate with the PDC for authentication and other > > > stuffs. So, i think it would work to configure ip > > > helper-address w.x.y.z on the ethernet interface of > > > router 1 only (where w.x.y.z is the ip address of your > > > PDC, but if you have multiple PDCs then you have to > > > give the directed-broadcast address and also have to > > > use ip directed-broadcast command). > > > > > > I hope this will work > > > > > > Muhammad Khalilullah > > > CCNP, MCSE > > > > > > --- David Eitel wrote: > > > > I have two routers connected via serial point to > > > > point link. Router 1 has > > > > an ethernet segment with PDC info I want forwarded > > > > to Router 2 ethernet > > > > segment. No ip directed broadcast is configured on > > > > all interfaces. I want > > > > netbios traffic passed from one segment to the > > > > other. I have placed an IP > > > > helper-address statement on the ethernet interface > > > > needing the help. Do I > > > > need to use the ip helper-address on all interfaces > > > > to the source ip > > > > helper-address? Is the ip forward-protocol also > > > > necessary? Any advice would > > > > be greatly appreciated > > > > > > > > David Eitel > > > > FAQ, list archives, and subscription info: > > > > http://www.groupstudy.com/list/cisco.html > > > > Report misconduct and Nondisclosure violations to > > > [EMAIL PROTECTED] > > > > > > > > > __ > > > Do You Yahoo!? > > > Get email at your own domain with Yahoo! Mail. > > > http://personal.mail.yahoo.com/ > > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=728&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
At 01:52 PM 4/15/01, Michael Snyder wrote: >I happen to be a ccnp and mcse. I get how ip helper-address works. Also >work with microsoft dhcp servers. > >How do you setup a scope for a remote subnet, and how does the dhcp server >know how to hand out the correct ip leases for a non-connected subnet? > >Does the dhcp server look at the source address of the interface of the >forwarded helper-address packets? Then match up the correct scope with the >router interface ip address? The source MAC address is the router's address (assuming the packet only went one hop), but the source IP address is 0.0.0.0, so that doesn't help. What does help is that the DHCP packet has a GIAddr (Gateway IP Address) field. The router that forwards the packet puts its own address in that field. The router puts the address for the interface that the DHCP Discover packet came in on. The remote DHCP server can figure out which scope it's dealing with from that info. The GIAddr should be from the same subnet as the requesting host. Priscilla >""Jason J. Roysdon"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Here's a fun link explaining ip helper: > > http://routergod.com/trinity/ > > > > -- > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ > > List email: [EMAIL PROTECTED] > > Homepage: http://jason.artoo.net/ > > > > > > > > ""Muhammed Khalilullah"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Actually, the IP helper command is placed on the > > > interface that is recieving the broadcasts. Now you > > > have to decide which router is supposed to recieve the > > > broadcasts. But in usual case, Clients usually try to > > > communcate with the PDC for authentication and other > > > stuffs. So, i think it would work to configure ip > > > helper-address w.x.y.z on the ethernet interface of > > > router 1 only (where w.x.y.z is the ip address of your > > > PDC, but if you have multiple PDCs then you have to > > > give the directed-broadcast address and also have to > > > use ip directed-broadcast command). > > > > > > I hope this will work > > > > > > Muhammad Khalilullah > > > CCNP, MCSE > > > > > > --- David Eitel wrote: > > > > I have two routers connected via serial point to > > > > point link. Router 1 has > > > > an ethernet segment with PDC info I want forwarded > > > > to Router 2 ethernet > > > > segment. No ip directed broadcast is configured on > > > > all interfaces. I want > > > > netbios traffic passed from one segment to the > > > > other. I have placed an IP > > > > helper-address statement on the ethernet interface > > > > needing the help. Do I > > > > need to use the ip helper-address on all interfaces > > > > to the source ip > > > > helper-address? Is the ip forward-protocol also > > > > necessary? Any advice would > > > > be greatly appreciated > > > > > > > > David Eitel > > > > FAQ, list archives, and subscription info: > > > > http://www.groupstudy.com/list/cisco.html > > > > Report misconduct and Nondisclosure violations to > > > [EMAIL PROTECTED] > > > > > > > > > __ > > > Do You Yahoo!? > > > Get email at your own domain with Yahoo! Mail. > > > http://personal.mail.yahoo.com/ > > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=736&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
Yes, The DHCP server will check the IP address of the interface on which you have configured the IP Helper address command. So make pools on the DHCP server accordingly. eg: Router's interface 192.168.1.1/16 Server' pool 192.168.0.1-192.168.255.254 wil work. Muhammad Khalilullah CCNP, MCSE --- "Jason J. Roysdon" wrote: > Yup, you got it. Just set up the extra scope(s) for > the subnet(s) you have > the ip helper-address enabled port(s) on. The DHCP > server sees the source > address (or perhaps network address/mask, I'm not > sure the down and dirty > details), and sends an appropriate DHCP address from > the scope that fits > that subnet. > > -- > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, > Network+, A+ > List email: [EMAIL PROTECTED] > Homepage: http://jason.artoo.net/ > > > > ""Michael Snyder"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > I happen to be a ccnp and mcse. I get how ip > helper-address works. Also > > work with microsoft dhcp servers. > > > > How do you setup a scope for a remote subnet, and > how does the dhcp server > > know how to hand out the correct ip leases for a > non-connected subnet? > > > > Does the dhcp server look at the source address of > the interface of the > > forwarded helper-address packets? Then match up > the correct scope with > the > > router interface ip address? > > > > > > > > > > ""Jason J. Roysdon"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Here's a fun link explaining ip helper: > > > http://routergod.com/trinity/ > > > > > > -- > > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, > Network+, A+ > > > List email: [EMAIL PROTECTED] > > > Homepage: http://jason.artoo.net/ > > > > > > > > > > > > ""Muhammed Khalilullah"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Actually, the IP helper command is placed on > the > > > > interface that is recieving the broadcasts. > Now you > > > > have to decide which router is supposed to > recieve the > > > > broadcasts. But in usual case, Clients usually > try to > > > > communcate with the PDC for authentication and > other > > > > stuffs. So, i think it would work to configure > ip > > > > helper-address w.x.y.z on the ethernet > interface of > > > > router 1 only (where w.x.y.z is the ip address > of your > > > > PDC, but if you have multiple PDCs then you > have to > > > > give the directed-broadcast address and also > have to > > > > use ip directed-broadcast command). > > > > > > > > I hope this will work > > > > > > > > Muhammad Khalilullah > > > > CCNP, MCSE > > > > > > > > --- David Eitel wrote: > > > > > I have two routers connected via serial > point to > > > > > point link. Router 1 has > > > > > an ethernet segment with PDC info I want > forwarded > > > > > to Router 2 ethernet > > > > > segment. No ip directed broadcast is > configured on > > > > > all interfaces. I want > > > > > netbios traffic passed from one segment to > the > > > > > other. I have placed an IP > > > > > helper-address statement on the ethernet > interface > > > > > needing the help. Do I > > > > > need to use the ip helper-address on all > interfaces > > > > > to the source ip > > > > > helper-address? Is the ip forward-protocol > also > > > > > necessary? Any advice would > > > > > be greatly appreciated > > > > > > > > > > David Eitel > > > > > FAQ, list archives, and subscription info: > > > > > http://www.groupstudy.com/list/cisco.html > > > > > Report misconduct and Nondisclosure > violations to > > > > [EMAIL PROTECTED] > > > > > > > > > > > > > __ > > > > Do You Yahoo!? > > > > Get email at your own domain with Yahoo! Mail. > > > > http://personal.mail.yahoo.com/ > > > > FAQ, list archives, and subscription info: > > > http://www.groupstudy.com/list/cisco.html > > > > Report misconduct and Nondisclosure violations > to [EMAIL PROTECTED] > > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > > Report misconduct and Nondisclosure violations > to [EMAIL PROTECTED] > > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to > [EMAIL PROTECTED] > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=758&t=247 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP Helper-address questions [7:247]
Actually, you'll want to make the pools only as big as the subnet, unless you know some trick I don't Muhammed. Each pool will need a default gateway assigned as part of the scope, and unless you're doing a /16 range for 192.168/16, then you'll want a pool for each 192.168/24 network. Don't forget to take advantage of the global attributes. Set your DNS, WINS, and whatever settings are the same for each pool as a global setting, and only those settings that need to be unique for each pool (Gateway is all I can think of). This way you don't have to specify these same settings for each pool. A pool-specific attribute will also override the Global attribute for that pool, so even if you had a local WINS and/or DNS server that you want one network to use, still set the Global for whatever is the main configuration. Don't forget if you use WINS to set the node type to 0x8 (hybrid). -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ ""Muhammed Khalilullah"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Yes, The DHCP server will check the IP address of the > interface on which you have configured the IP Helper > address command. So make pools on the DHCP server > accordingly. eg: Router's interface 192.168.1.1/16 > Server' pool 192.168.0.1-192.168.255.254 wil work. > > Muhammad Khalilullah > CCNP, MCSE > --- "Jason J. Roysdon" wrote: > > Yup, you got it. Just set up the extra scope(s) for > > the subnet(s) you have > > the ip helper-address enabled port(s) on. The DHCP > > server sees the source > > address (or perhaps network address/mask, I'm not > > sure the down and dirty > > details), and sends an appropriate DHCP address from > > the scope that fits > > that subnet. > > > > -- > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, > > Network+, A+ > > List email: [EMAIL PROTECTED] > > Homepage: http://jason.artoo.net/ > > > > > > > > ""Michael Snyder"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > I happen to be a ccnp and mcse. I get how ip > > helper-address works. Also > > > work with microsoft dhcp servers. > > > > > > How do you setup a scope for a remote subnet, and > > how does the dhcp server > > > know how to hand out the correct ip leases for a > > non-connected subnet? > > > > > > Does the dhcp server look at the source address of > > the interface of the > > > forwarded helper-address packets? Then match up > > the correct scope with > > the > > > router interface ip address? > > > > > > > > > > > > > > > ""Jason J. Roysdon"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Here's a fun link explaining ip helper: > > > > http://routergod.com/trinity/ > > > > > > > > -- > > > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, > > Network+, A+ > > > > List email: [EMAIL PROTECTED] > > > > Homepage: http://jason.artoo.net/ > > > > > > > > > > > > > > > > ""Muhammed Khalilullah"" wrote in message > > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > > Actually, the IP helper command is placed on > > the > > > > > interface that is recieving the broadcasts. > > Now you > > > > > have to decide which router is supposed to > > recieve the > > > > > broadcasts. But in usual case, Clients usually > > try to > > > > > communcate with the PDC for authentication and > > other > > > > > stuffs. So, i think it would work to configure > > ip > > > > > helper-address w.x.y.z on the ethernet > > interface of > > > > > router 1 only (where w.x.y.z is the ip address > > of your > > > > > PDC, but if you have multiple PDCs then you > > have to > > > > > give the directed-broadcast address and also > > have to > > > > > use ip directed-broadcast command). > > > > > > > > > > I hope this will work > > > > > > > > > > Muhammad Khalilullah > > > > > CCNP, MCSE > > > > > > > > > > --- David Eitel wrote: > &g
Function of IP HELPER ADDRESS & IP DIRECTED BROADCAST ?
Hi guy, Could somebody explain what is the function of IP HELPER ADDRESS & IP DIRECTED BROADCAST. Thanks in advance. Syam _ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
IP helper-address, domain browsing & NAT [7:36089]
Does anyone know of any issues using the IP helper-address and domain browsing while using NAT? I have 2 locations, CA and NJ. CA has a connection to the internet, NJ does not. CA and NJ are connected via a point-to-point link via their serial insterfaces. With the help of NATting NJ now is able to access the internet via the router in CA. My problem is that I need the servers at each location to replicate their WINS databases. To try and solve this issues I added IP Helper-adress to the serial point to point link on both side. If I remove the ip nat inside or the ip nat outside command from either the fastethernet or the serail interfaces I can broswe the domain and replicate the Wins database in either location. But the NJ location does not have internet access. What do I need to do to enable both browsing to and from either location and Internet access at both locations. Here is a copy of my config from both locations. hostname California ! enable secret ! ! ! ! ! memory-size iomem 25 ip subnet-zero ! ! ! ! interface Serial0 description Connection to ISP ip address 10.0.10.1 255.255.255.252 ip nat outside no fair-queue interface Serial1 description point to point t1 to New Jersey ip address 192.168.254.2 255.255.255.252 ip helper-address 10.0.3.40 ***Server's IP in New Jersey* no fair-queue ! interface FastEthernet0 ip address 10.0.2.1 255.255.255.0 secondary ip address xxx.xxx.xxx.155 255.255.255.248 ip nat inside speed auto ! ip nat pool local xxx.xxx.xxx.155 xxx.xxx.xxx.155 prefix-length 28 ip nat inside source list 1 pool local overload ip nat inside source static 10.0.3.40 xxx.xxx.xxx.156 extendable ip classless ip route 0.0.0.0 0.0.0.0 serial0 ip route 10.0.3.0 255.255.255.0 192.168.254.1 ip route xxx.xxx.xxx.0 255.255.255.248 192.168.254.1 no ip http server ! access-list 1 permit 10.0.2.0 0.0.0.255 ! line con 0 password line aux 0 password line vty 0 4 password ! end hostname NewJersy ! enable secret ! ! ! ! ! memory-size iomem 25 ip subnet-zero ! ! ! ! interface Serial0 description point to point t1 to California ip address 192.168.254.1 255.255.255.252 ip nat outside no fair-queue service-module t1 timeslots 1-24 ! interface FastEthernet0 ip address 10.0.3.1 255.255.255.0 secondary ip address xxx.xxx.xxx.46 255.255.255.248 ip helper-address 10.0.2.9 ***Server's IP in California* ip nat inside speed auto ! ip nat pool local xxx.xxx.xxx.46 xxx.xxx.xxx.46 prefix-length 28 ip nat inside source list 1 pool local overload ip nat inside source static 10.0.3.40 xxx.xxx.xxx.45 extendable ip classless ip route 0.0.0.0 0.0.0.0 192.168.254.2 no ip http server ! access-list 1 permit 10.0.3.0 0.0.0.255 ! line con 0 password line aux 0 password line vty 0 4 password ! end Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=36089&t=36089 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ip forward-protocol vs. ip helper-address
The "command ip helper-address" enables forwarding for eight UDP ports - time (37), TACACS (49), DNS (53), BOOTP/DHCP Server (67), BOOTP/DHCP Client (68), TFTP (69), NetBIOS Name Service (137) and NetBIOS Datagram Service (138). However, there may be times when you want to forward other UDP ports besides these 8. The command "ip-forward protocol" gives you more granularity over forwarding UDP datagrams. You literally can forward any UDP port from 0-65535 if you should so choose. Here's the output of the options which can be used with "ip forward-protocol" for Cisco IOS 11.2: <0-65535>Port number biff Biff (mail notification, comsat, 512) bootpc Bootstrap Protocol (BOOTP) client (68) bootps Bootstrap Protocol (BOOTP) server (67) discard Discard (9) dnsixDNSIX security protocol auditing (195) domain Domain Name Service (DNS, 53) echo Echo (7) mobile-ipMobile IP registration (434) nameserver IEN116 name service (obsolete, 42) netbios-dgm NetBios datagram service (138) netbios-ns NetBios name service (137) netbios-ss NetBios session service (139) ntp Network Time Protocol (123) rip Routing Information Protocol (router, in.routed, 520) snmp Simple Network Management Protocol (161) snmptrap SNMP Traps (162) sunrpc Sun Remote Procedure Call (111) syslog System Logger (514) tacacs TAC Access Control System (49) talk Talk (517) tftp Trivial File Transfer Protocol (69) time Time (37) who Who service (rwho, 513) xdmcpX Display Manager Control Protocol (177) > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Kent > Sent: Wednesday, August 16, 2000 9:43 AM > To: [EMAIL PROTECTED] > Subject: RE: ip forward-protocol vs. ip helper-address > > > Hi all, > > In the following config, which was cut from the CD, > why would we need the "ip forward-protocol" there, > I though the ip-helped address would do the job, to > forward all the broadcast to the servers, is that > right? > > Thanks > > Kent > > "In the following example, one router is on network > 191.24.1.0 and the other is on network 110.44.0.0, and > you want to permit IP broadcasts from hosts on either > network segment to reach both servers. Figure 14 > illustrates how to configure the router that connects > network 110 to network 191.24.1. > > > Figure 14: IP Helper Addresses > > The following example shows the configuration: > > ip forward-protocol udp > ! > interface ethernet 1 > ip helper-address 110.44.23.7 > interface ethernet 2 > ip helper-address 191.24.1.19 > > > > __ > Do You Yahoo!? > Send instant messages & get email alerts with Yahoo! Messenger. > http://im.yahoo.com/ > > ___ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ip forward-protocol vs. ip helper-address
Leigh, Thanks for your reply, I kind of know the difference of these two commands, but in the sample configure, which just uses the 'ip forward protocol' without any parameter, does it just by default enables forwarding those 8 ports too? I was confused by its using the 'ip forward protocol' without paratmeter with 'ip hleper-address' together, what is the point of this? Do they just enable the same ports? As this is from the CD, I think it should have some meanings, maybe not, I just want to get some comments on my doubts. Thanks Kent --- Leigh Anne Chisholm <[EMAIL PROTECTED]> wrote: > The "command ip helper-address" enables forwarding > for eight UDP ports - time (37), TACACS (49), DNS > (53), BOOTP/DHCP Server (67), BOOTP/DHCP Client > (68), TFTP (69), NetBIOS Name Service (137) and > NetBIOS Datagram Service (138). However, there may > be times when you want to forward other UDP ports > besides these 8. > > The command "ip-forward protocol" gives you more > granularity over forwarding UDP datagrams. You > literally can forward any UDP port from 0-65535 if > you should so choose. Here's the output of the > options which can be used with "ip forward-protocol" > for Cisco IOS 11.2: > > <0-65535>Port number > biff Biff (mail notification, comsat, 512) > bootpc Bootstrap Protocol (BOOTP) client > (68) > bootps Bootstrap Protocol (BOOTP) server > (67) > discard Discard (9) > dnsixDNSIX security protocol auditing > (195) > domain Domain Name Service (DNS, 53) > echo Echo (7) > mobile-ipMobile IP registration (434) > nameserver IEN116 name service (obsolete, 42) > netbios-dgm NetBios datagram service (138) > netbios-ns NetBios name service (137) > netbios-ss NetBios session service (139) > ntp Network Time Protocol (123) > rip Routing Information Protocol (router, > in.routed, 520) > snmp Simple Network Management Protocol > (161) > snmptrap SNMP Traps (162) > sunrpc Sun Remote Procedure Call (111) > syslog System Logger (514) > tacacs TAC Access Control System (49) > talk Talk (517) > tftp Trivial File Transfer Protocol (69) > time Time (37) > who Who service (rwho, 513) > xdmcpX Display Manager Control Protocol > (177) > > > -Original Message- > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of > > Kent > > Sent: Wednesday, August 16, 2000 9:43 AM > > To: [EMAIL PROTECTED] > > Subject: RE: ip forward-protocol vs. ip > helper-address > > > > > > Hi all, > > > > In the following config, which was cut from the > CD, > > why would we need the "ip forward-protocol" there, > > I though the ip-helped address would do the job, > to > > forward all the broadcast to the servers, is that > > right? > > > > Thanks > > > > Kent > > > > "In the following example, one router is on > network > > 191.24.1.0 and the other is on network 110.44.0.0, > and > > you want to permit IP broadcasts from hosts on > either > > network segment to reach both servers. Figure 14 > > illustrates how to configure the router that > connects > > network 110 to network 191.24.1. > > > > > > Figure 14: IP Helper Addresses > > > > The following example shows the configuration: > > > > ip forward-protocol udp > > ! > > interface ethernet 1 > > ip helper-address 110.44.23.7 > > interface ethernet 2 > > ip helper-address 191.24.1.19 > > > > > > > > __ > > Do You Yahoo!? > > Send instant messages & get email alerts with > Yahoo! Messenger. > > http://im.yahoo.com/ > > > > ___ > > UPDATED Posting Guidelines: > http://www.groupstudy.com/list/guide.html > > FAQ, list archives, and subscription info: > http://www.groupstudy.com > > Report misconduct and Nondisclosure violations to > [EMAIL PROTECTED] > > > > ___ > UPDATED Posting Guidelines: > http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: > http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Send instant messages & get email alerts with Yahoo! Messenger. http://im.yahoo.com/ ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ip forward-protocol vs. ip helper-address
Hi all, In the following config, which was cut from the CD, why would we need the "ip forward-protocol" there, I though the ip-helped address would do the job, to forward all the broadcast to the servers, is that right? Thanks Kent "In the following example, one router is on network 191.24.1.0 and the other is on network 110.44.0.0, and you want to permit IP broadcasts from hosts on either network segment to reach both servers. Figure 14 illustrates how to configure the router that connects network 110 to network 191.24.1. Figure 14: IP Helper Addresses The following example shows the configuration: ip forward-protocol udp ! interface ethernet 1 ip helper-address 110.44.23.7 interface ethernet 2 ip helper-address 191.24.1.19 __ Do You Yahoo!? Send instant messages & get email alerts with Yahoo! Messenger. http://im.yahoo.com/ ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Function of IP HELPER ADDRESS & IP DIRECTED BROADCAST ?
ip helper-address is used to relay BOOTP/DHCP and other services from the attached network to a known point on your network (the helper address). ip directed-broadcasts allows you to forward broadcast pings, etc. This should typically be turned off unless you really need to use it. See http://www.cisco.com/univercd/cc/td/doc/product/software/ssr83/rpc_r/48383.h tm for more on both subjects. ""norsyam ariffin"" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Hi guy, > > Could somebody explain what is the function of IP HELPER ADDRESS & IP > DIRECTED BROADCAST. > > Thanks in advance. > > Syam > _ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Function of IP HELPER ADDRESS & IP DIRECTED BROADCAST ?
Router by-default doesn't forward the broadcast storm. So any application that requires broadcast to be forwarded to another subnet wiould be blocked by the router. Taking the example of DHCP Server & Client. A DHCP Client machine on bootup sends broadcast in search of a BBOTP Server. As long as this server is in the same subnet, an IP address will be automatically assigned to that machine. However if the DHCP server is on another subnet, this broadcast will no be forwarded to that subnet (The behaviour of a Router) unless we specify the IP HELPER-ADDRESS w.x.y.z command on the interface that is recieving the broadcast (i.e. the interface with subnet of client's machine). this command actually converts the broadcast to a unicast address, where the unicast address is specified by the IP address of the DHCP server specified in the Helper-address command. As long as there is only one DHCP server you require nothing else (i.e no requirement for IP DIRECTED-BROADCAST command) but if there are multiple dhcp servers on the same subnet you have to define the directed broadcast address in the ip helper-address command. Eg if the network is 10.1.1.0/24 then the directed-broadcast address would be 10.1.1.255. In this case you have to define ip directed-broadcast command on the interfaces. Muhammad Khalilullah Network Engineer CCNP, MCSE --- norsyam ariffin <[EMAIL PROTECTED]> wrote: > Hi guy, > > Could somebody explain what is the function of IP > HELPER ADDRESS & IP > DIRECTED BROADCAST. > > Thanks in advance. > > Syam > _ > Get Your Private, Free E-mail from MSN Hotmail at > http://www.hotmail.com. > > _ > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP helper address and subnet broadcast [7:25692]
sorry if you've received this before...I'm having problems posting it seems... -Original Message- From: R. Benjamin Kessler [mailto:[EMAIL PROTECTED]] Sent: Thursday, November 08, 2001 10:01 AM To: Priscilla Oppenheimer; Cisco GroupStudy List Subject: RE: IP helper address and subnet broadcast [7:25485] I had a similar situation in the past where the DHCP servers were on *nix boxes and they got flooded with the NetBT stuff (from 3000+ workstations) needlessly. In this type of a situation "no ip forward protocol" is your friend. To just foward the DHCP requests you need to do the following: no ip forward-protocol udp tftp no ip forward-protocol udp nameserver no ip forward-protocol udp domain no ip forward-protocol udp time no ip forward-protocol udp netbios-ns no ip forward-protocol udp netbios-dgm no ip forward-protocol udp tacacs It would be nice if you could disable all and then specifically add the ones you want (i.e. the passive-interface default / no passive-interface method) but - at least on the versions I've tried - she's a no go. You can disable all udp flooding with the command: no ip forward-protocol udp But as soon as you enable a specific service this command gets 'un-done'...perhaps a it can be a feature request for the programmers @ Cisco watching this list (do any?). Hope this helps. Ben -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Wednesday, November 07, 2001 2:44 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: IP helper address and subnet broadcast [7:25485] Thank-you very much for your research and testing, Ben. The person who started this discussion (offline) also wrote back and confirmed that the subnet broadcasts are indeed forwarded to the address in his IP helper address command. I agree that it makes sense from the point of view that the subnet broadcast (10.10.255.255) is no different from an ordinary broadcast (255.255.255.255) at the MAC layer. They both go to FF:FF:FF:FF:FF:FF. There are concerns about this behavior however. In his case the DHCP server is the helper address. It is receiving all sorts of junk that it shouldn't receive, including WINS and BROWSE stuff. The IP Helper Address configuration is causing these packets to be sent as unicast packets to the DHCP server. It's probably just a minor performance issue, but worth fixing. I don't know enough about his network to recommend this definitely, but he may be able to configure "no ip forward-protocol 137" and "no ip forward-protocol 138" to ensure that the WINS and BROWSE stuff is not forwarded. I believe he has an actual WINS server also that can handle the WINS service and the nodes are configured as H-Nodes so they are unicasting to the WINS server in addition to sending their broadcasts. I thought this was interesting! I wonder how many people have thought about how much junk by default gets forwarded with IP helper address. And offline, some experts asked me why would a router forward a subnet broadcast, so they all agreed that this was not completely expected behavior. Thanks again, Priscilla At 10:00 AM 11/7/01, R. Benjamin Kessler wrote: >I setup a remote unix box running nmap and had it send packets to the subnet >broadcast address (in my case 192.168.72.255). I configured my router with >an ip helper command (sending to a single host). I executed the nmap >command with and without IP directed broadcast configured on the router >interface and didn't see any difference. > >Running a sniffer-like device on the target (of the ip helper command) I was >able to verify the receipt of the packets sent via nmap. > >Given a network similar to the following: > > +---++---+ >-| rtr a || rtr b |- > e0 +---+ e1 e1 +---+ e0 > >My understanding of directed-broadcast is that if a packet sourced from rtr >a's e0 network is sent to the broadcast address of rtr b's e0; rtr b will >forward it if directed-broadcast is enabled and drop if not. > >IP helper impacts packets heading out (from the router) to the interface in >question not packets inbound. > >To take this discussion a step further, the IP helper function processes >packets sent to the MAC-layer broadcast address for the specified protocols. >A packet sent to the local IP broadcast address (10.10.255.255 in >Priscilla's example) will have the same MAC-layer destination address as a >packet sent to 255.255.255.255. > >Comments, questions? Anyone think my logic is all wet? > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of >Priscilla Oppenheimer >Sent: Tuesday, November 06, 2001 9:43 PM >To: [EMAIL PROTECTED] >Subject: Re: IP helper address and subnet broadcast [7:25485] > > >I know
Re: IP helper address and subnet broadcast [7:25485]
Priscilla Oppenheimer wrote: > Thank-you very much for your research and testing, Ben. > > The person who started this discussion (offline) also wrote back and > confirmed that the subnet broadcasts are indeed forwarded to the address in > his IP helper address command. I agree that it makes sense from the point > of view that the subnet broadcast (10.10.255.255) is no different from an > ordinary broadcast (255.255.255.255) at the MAC layer. They both go to > FF:FF:FF:FF:FF:FF. > > There are concerns about this behavior however. In his case the DHCP server > is the helper address. It is receiving all sorts of junk that it shouldn't > receive, including WINS and BROWSE stuff. The IP Helper Address > configuration is causing these packets to be sent as unicast packets to the > DHCP server. It's probably just a minor performance issue, but worth fixing. > > I don't know enough about his network to recommend this definitely, but he > may be able to configure "no ip forward-protocol 137" and "no ip > forward-protocol 138" to ensure that the WINS and BROWSE stuff is not > forwarded. I believe he has an actual WINS server also that can handle the > WINS service and the nodes are configured as H-Nodes so they are unicasting > to the WINS server in addition to sending their broadcasts. > > I thought this was interesting! I wonder how many people have thought about > how much junk by default gets forwarded with IP helper address. And > offline, some experts asked me why would a router forward a subnet > broadcast, so they all agreed that this was not completely expected behavior. > > Thanks again, > > Priscilla > > At 10:00 AM 11/7/01, R. Benjamin Kessler wrote: > >I setup a remote unix box running nmap and had it send packets to the subnet > >broadcast address (in my case 192.168.72.255). I configured my router with > >an ip helper command (sending to a single host). I executed the nmap > >command with and without IP directed broadcast configured on the router > >interface and didn't see any difference. > > > >Running a sniffer-like device on the target (of the ip helper command) I was > >able to verify the receipt of the packets sent via nmap. > > > >Given a network similar to the following: > > > > +---++---+ > >-| rtr a || rtr b |- > > e0 +---+ e1 e1 +---+ e0 > > > >My understanding of directed-broadcast is that if a packet sourced from rtr > >a's e0 network is sent to the broadcast address of rtr b's e0; rtr b will > >forward it if directed-broadcast is enabled and drop if not. > > > >IP helper impacts packets heading out (from the router) to the interface in > >question not packets inbound. > > > >To take this discussion a step further, the IP helper function processes > >packets sent to the MAC-layer broadcast address for the specified protocols. > >A packet sent to the local IP broadcast address (10.10.255.255 in > >Priscilla's example) will have the same MAC-layer destination address as a > >packet sent to 255.255.255.255. > > > >Comments, questions? Anyone think my logic is all wet? > > > >-Original Message- > >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > >Priscilla Oppenheimer > >Sent: Tuesday, November 06, 2001 9:43 PM > >To: [EMAIL PROTECTED] > >Subject: Re: IP helper address and subnet broadcast [7:25485] > > > > > >I know how IP helper address, directed broadcasts, NetBIOS, etc. work. > >(NetBIOS session service doesn't broadcast, by the way, and in fact uses > >TCP not UDP, so I doubt that it needs to be added to the list. It's used > >between a client and server after the client has mapped the NetBIOS name to > >the server's address.) > > > >The question is: will the router (with IP helper address) forward if the > >source sends to a subnet broadcast such as 10.10.255.255 instead of sending > >to 255.255.255.255? Nowhere does the documentation say that it won't, so I > >guess it will. > > > >Note that I am not asking about the forwarding of directed broadcasts. The > >IP helper address is configured with an actual server's address, not a > >directed broadcast address. > > > >I'm not looking for the boring answers to the boring questions. The > >question is not the same one that you have seen many times. ;-) > > > >Priscilla > > > > Priscilla Oppenheimer > http://www.priscilla.com Many of the big corporations have been aware of it for some time. When I had to set up DHCP at a certain Silicon Valley giant corporation in 1996, I came across their white paper on setting up DHCP relay via Cisco's ip helper-address, with specific instructions to do a "no ip forward" on UDP 137 and 138. Jonathan Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=25734&t=25485 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: IP helper address and subnet broadcast [7:25485]
I had a similar situation in the past where the DHCP servers were on *nix boxes and they got flooded with the NetBT stuff (from 3000+ workstations) needlessly. In this type of a situation "no ip forward protocol" is your friend. To just foward the DHCP requests you need to do the following: no ip forward-protocol udp tftp no ip forward-protocol udp nameserver no ip forward-protocol udp domain no ip forward-protocol udp time no ip forward-protocol udp netbios-ns no ip forward-protocol udp netbios-dgm no ip forward-protocol udp tacacs It would be nice if you could disable all and then specifically add the ones you want (i.e. the passive-interface default / no passive-interface method) but - at least on the versions I've tried - she's a no go. You can disable all udp flooding with the command: no ip forward-protocol udp But as soon as you enable a specific service this command gets 'un-done'...perhaps a it can be a feature request for the programmers @ Cisco watching this list (do any?). Hope this helps. Ben -Original Message- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Wednesday, November 07, 2001 2:44 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: IP helper address and subnet broadcast [7:25485] Thank-you very much for your research and testing, Ben. The person who started this discussion (offline) also wrote back and confirmed that the subnet broadcasts are indeed forwarded to the address in his IP helper address command. I agree that it makes sense from the point of view that the subnet broadcast (10.10.255.255) is no different from an ordinary broadcast (255.255.255.255) at the MAC layer. They both go to FF:FF:FF:FF:FF:FF. There are concerns about this behavior however. In his case the DHCP server is the helper address. It is receiving all sorts of junk that it shouldn't receive, including WINS and BROWSE stuff. The IP Helper Address configuration is causing these packets to be sent as unicast packets to the DHCP server. It's probably just a minor performance issue, but worth fixing. I don't know enough about his network to recommend this definitely, but he may be able to configure "no ip forward-protocol 137" and "no ip forward-protocol 138" to ensure that the WINS and BROWSE stuff is not forwarded. I believe he has an actual WINS server also that can handle the WINS service and the nodes are configured as H-Nodes so they are unicasting to the WINS server in addition to sending their broadcasts. I thought this was interesting! I wonder how many people have thought about how much junk by default gets forwarded with IP helper address. And offline, some experts asked me why would a router forward a subnet broadcast, so they all agreed that this was not completely expected behavior. Thanks again, Priscilla At 10:00 AM 11/7/01, R. Benjamin Kessler wrote: >I setup a remote unix box running nmap and had it send packets to the subnet >broadcast address (in my case 192.168.72.255). I configured my router with >an ip helper command (sending to a single host). I executed the nmap >command with and without IP directed broadcast configured on the router >interface and didn't see any difference. > >Running a sniffer-like device on the target (of the ip helper command) I was >able to verify the receipt of the packets sent via nmap. > >Given a network similar to the following: > > +---++---+ >-| rtr a || rtr b |- > e0 +---+ e1 e1 +---+ e0 > >My understanding of directed-broadcast is that if a packet sourced from rtr >a's e0 network is sent to the broadcast address of rtr b's e0; rtr b will >forward it if directed-broadcast is enabled and drop if not. > >IP helper impacts packets heading out (from the router) to the interface in >question not packets inbound. > >To take this discussion a step further, the IP helper function processes >packets sent to the MAC-layer broadcast address for the specified protocols. >A packet sent to the local IP broadcast address (10.10.255.255 in >Priscilla's example) will have the same MAC-layer destination address as a >packet sent to 255.255.255.255. > >Comments, questions? Anyone think my logic is all wet? > >-Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of >Priscilla Oppenheimer >Sent: Tuesday, November 06, 2001 9:43 PM >To: [EMAIL PROTECTED] >Subject: Re: IP helper address and subnet broadcast [7:25485] > > >I know how IP helper address, directed broadcasts, NetBIOS, etc. work. >(NetBIOS session service doesn't broadcast, by the way, and in fact uses >TCP not UDP, so I doubt that it needs to be added to the list. It's used >between a client and server after the client has mapped the NetBIOS name to >the server'
RE: IP helper address and subnet broadcast [7:25485]
Depends on what you're trying to do...the utility I used here is just "nmap" - see www.insecure.org (note: this is a bit of a "hacking" tool, so use with caution). This is basically a port scanning tool, you can specify a remote subnet to scan but you give it the range of addresses to probe, I don't see why you couldn't probe a remote host that just happened to have the same address as the subnet broadcast somewhere. I guess by definition, if you've got a default gateway configured and are sending traffic to a remote subnet you'll have the local router's MAC address as the destination. If you're looking to do something a bit more elaborate you can try to use a Sniffer to manufacture a string of packets but it is probably more trouble than it's worth. I'm sure that there are plenty of hacker tools that will do this but you'll probably need to go lurking on some different lists to find them... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Logan, Harold Sent: Wednesday, November 07, 2001 2:32 PM To: [EMAIL PROTECTED] Subject: RE: IP helper address and subnet broadcast [7:25485] Interesting... By any chance do you have a packet manipulator available? For added fun you could put together a frame with a destination IP of the subnet's broadcast addy, and a destination MAC of the routers MAC address... > -Original Message- > From: R. Benjamin Kessler [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, November 07, 2001 2:03 PM > To: [EMAIL PROTECTED] > Subject: RE: IP helper address and subnet broadcast [7:25485] > > > I setup a remote unix box running nmap and had it send > packets to the subnet > broadcast address (in my case 192.168.72.255). I configured > my router with > an ip helper command (sending to a single host). I executed the nmap > command with and without IP directed broadcast configured on > the router > interface and didn't see any difference. > > Running a sniffer-like device on the target (of the ip helper > command) I was > able to verify the receipt of the packets sent via nmap. > > Given a network similar to the following: > > +---++---+ > -| rtr a || rtr b |- > e0 +---+ e1 e1 +---+ e0 > > My understanding of directed-broadcast is that if a packet > sourced from rtr > a's e0 network is sent to the broadcast address of rtr b's > e0; rtr b will > forward it if directed-broadcast is enabled and drop if not. > > IP helper impacts packets heading out (from the router) to > the interface in > question not packets inbound. > > To take this discussion a step further, the IP helper > function processes > packets sent to the MAC-layer broadcast address for the > specified protocols. > A packet sent to the local IP broadcast address (10.10.255.255 in > Priscilla's example) will have the same MAC-layer destination > address as a > packet sent to 255.255.255.255. > > Comments, questions? Anyone think my logic is all wet? > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Priscilla Oppenheimer > Sent: Tuesday, November 06, 2001 9:43 PM > To: [EMAIL PROTECTED] > Subject: Re: IP helper address and subnet broadcast [7:25485] > > > I know how IP helper address, directed broadcasts, NetBIOS, etc. work. > (NetBIOS session service doesn't broadcast, by the way, and > in fact uses > TCP not UDP, so I doubt that it needs to be added to the > list. It's used > between a client and server after the client has mapped the > NetBIOS name to > the server's address.) > > The question is: will the router (with IP helper address) > forward if the > source sends to a subnet broadcast such as 10.10.255.255 > instead of sending > to 255.255.255.255? Nowhere does the documentation say that > it won't, so I > guess it will. > > Note that I am not asking about the forwarding of directed > broadcasts. The > IP helper address is configured with an actual server's address, not a > directed broadcast address. > > I'm not looking for the boring answers to the boring questions. The > question is not the same one that you have seen many times. ;-) > > Priscilla > > At 10:09 PM 11/6/01, Erick B. wrote: > >Priscalla, > > > >They need to enable one more 'ip forward-protocol udp' > >globally for this to work, as well as enable > >directed-broadcast on target router interface where > >ip-helper is forwarding to. > > > >Also, I replied to nrf on this as well in more detail > >just explaining helper-address and > >directed-broadcasts. > > > >
RE: IP helper address and subnet broadcast [7:25485]
The few times I've needed a packet manipulator, SnifferPro has worked fine for me. The idea I was shooting for (please keep in mind that yesterday I was working on 3 hours of sleep and no caffeine) was to put together a layer 3 broadcast with a layer 2 unicast address, specifically the destination MAC of the router's ethernet interface. That, combined with some packet debugging or accounting on the far router, could tell you if the router forwards traffic to the ip helper address because the layer 2 destination addy is all F's, or if it forwards to the ip helper addres because the layer 3 destination address is the subnet's broadcast addy. I suppose if I'm that curious I should get off my arse and set up such a scenario here, but I let someone else label the cables in my pod, and I'm still working on fixing it... right now the classroom where we keep the routers has v.35 and cat5 cables strewn all over the place. Argh. Hal Logan Network Specialist / Adjunct Faculty Computing and Engineering Technology Manatee Community College > -Original Message- > From: R. Benjamin Kessler [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, November 07, 2001 5:18 PM > To: Logan, Harold; [EMAIL PROTECTED] > Subject: RE: IP helper address and subnet broadcast [7:25485] > > > Depends on what you're trying to do...the utility I used here is just > "nmap" - see www.insecure.org (note: this is a bit of a > "hacking" tool, so > use with caution). > > This is basically a port scanning tool, you can specify a > remote subnet to > scan but you give it the range of addresses to probe, I don't > see why you > couldn't probe a remote host that just happened to have the > same address as > the subnet broadcast somewhere. > > I guess by definition, if you've got a default gateway > configured and are > sending traffic to a remote subnet you'll have the local router's MAC > address as the destination. > > If you're looking to do something a bit more elaborate you > can try to use a > Sniffer to manufacture a string of packets but it is probably > more trouble > than it's worth. I'm sure that there are plenty of hacker > tools that will > do this but you'll probably need to go lurking on some > different lists to > find them... > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > Logan, Harold > Sent: Wednesday, November 07, 2001 2:32 PM > To: [EMAIL PROTECTED] > Subject: RE: IP helper address and subnet broadcast [7:25485] > > > Interesting... By any chance do you have a packet manipulator > available? > For added fun you could put together a frame with a destination IP of > the subnet's broadcast addy, and a destination MAC of the routers MAC > address... > > > > -Original Message- > > From: R. Benjamin Kessler [mailto:[EMAIL PROTECTED]] > > Sent: Wednesday, November 07, 2001 2:03 PM > > To: [EMAIL PROTECTED] > > Subject: RE: IP helper address and subnet broadcast [7:25485] > > > > > > I setup a remote unix box running nmap and had it send > > packets to the subnet > > broadcast address (in my case 192.168.72.255). I configured > > my router with > > an ip helper command (sending to a single host). I > executed the nmap > > command with and without IP directed broadcast configured on > > the router > > interface and didn't see any difference. > > > > Running a sniffer-like device on the target (of the ip helper > > command) I was > > able to verify the receipt of the packets sent via nmap. > > > > Given a network similar to the following: > > > > +---++---+ > > -| rtr a || rtr b |- > > e0 +---+ e1 e1 +---+ e0 > > > > My understanding of directed-broadcast is that if a packet > > sourced from rtr > > a's e0 network is sent to the broadcast address of rtr b's > > e0; rtr b will > > forward it if directed-broadcast is enabled and drop if not. > > > > IP helper impacts packets heading out (from the router) to > > the interface in > > question not packets inbound. > > > > To take this discussion a step further, the IP helper > > function processes > > packets sent to the MAC-layer broadcast address for the > > specified protocols. > > A packet sent to the local IP broadcast address (10.10.255.255 in > > Priscilla's example) will have the same MAC-layer destination > > address as a > > packet sent to 255.255.255.255. > > > > Comments, questions? Anyone think my logi
Secondary ip address and ip helper-address HELPPPPPPPPPPPPPP [7:35532]
Team, I have the following problem: Our network has 10 sites, I am in the process of readdressing current network. I have setup secondary ip address on every site, At the present time I am setting up a wk2000 dhcp/win server in one site. The problem is that I am not able to obtain ip address from the DHCP server via the WAN, it works fine in the site where it is locate. The layout is the following: Hub site interface Ethernet0 ip address 192.168.13.1 255.255.255.0 secondary ip address 192.168.1.1 255.255.255.0 ip helper-address 192.168.12.17 ip directed-broadcast no cdp enable interface Serial0 no ip address ip directed-broadcast encapsulation frame-relay IETF no ip mroute-cache frame-relay lmi-type ansi interface Serial0.3 point-to-point description Spoke site bandwidth 384 ip unnumbered Ethernet0 ip helper-address 192.168.12.17 ip directed-broadcast frame-relay interface-dlci 26 Spoke site interface Ethernet0 ip address 192.168.12.1 255.255.255.0 secondary ip address 192.168.2.1 255.255.255.0 interface Serial0 no ip address encapsulation frame-relay IETF no fair-queue frame-relay lmi-type ansi ! interface Serial0.1 point-to-point description connection to Hub ip unnumbered Ethernet0 bandwidth 384 frame-relay interface-dlci 16 ! The ip address of the DHCP sever is 192.168.12.17 Be aware that I have not problem pinging to the DHCP server from the Hub site. Team, what I am doing wrong here...HELP Thanks (nothing can replace experiencewo) JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35532&t=35532 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35533]
I bet the clients are on the new secondary networks? Is that true, because if so, ip helper only works on the primary interface's address and not on the clients on the secondary network. It won't pick up the secondary networks broadcasts. -- RFC 1149 Compliant. ""J-B"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Team, > I have the following problem: > > Our network has 10 sites, I am in the process of readdressing current > network. I have setup secondary ip address on every site, At the present > time I am setting up a wk2000 dhcp/win server in one site. The problem is > that I am not able to obtain ip address from the DHCP server via the WAN, it > works fine in the site where it is locate. The layout is the following: > > Hub site > > interface Ethernet0 > ip address 192.168.13.1 255.255.255.0 secondary > ip address 192.168.1.1 255.255.255.0 > ip helper-address 192.168.12.17 > ip directed-broadcast > no cdp enable > > interface Serial0 > no ip address > ip directed-broadcast > encapsulation frame-relay IETF > no ip mroute-cache > frame-relay lmi-type ansi > > interface Serial0.3 point-to-point > description Spoke site > bandwidth 384 > ip unnumbered Ethernet0 > ip helper-address 192.168.12.17 > ip directed-broadcast > frame-relay interface-dlci 26 > > Spoke site > > interface Ethernet0 > ip address 192.168.12.1 255.255.255.0 secondary > ip address 192.168.2.1 255.255.255.0 > > interface Serial0 > no ip address > encapsulation frame-relay IETF > no fair-queue > frame-relay lmi-type ansi > ! > interface Serial0.1 point-to-point > description connection to Hub > ip unnumbered Ethernet0 > bandwidth 384 > frame-relay interface-dlci 16 > ! > > The ip address of the DHCP sever is 192.168.12.17 > > Be aware that I have not problem pinging to the DHCP server from the Hub > site. > > Team, what I am doing wrong here...HELP > > > Thanks (nothing can replace experiencewo) > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35533&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35533]
Well the clients have not ip address, what we are doing is remove all ip address from the clients and enable DHCP ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I bet the clients are on the new secondary networks? Is that true, because > if so, ip helper only works on the primary interface's address and not on > the clients on the secondary network. It won't pick up the secondary > networks broadcasts. > > -- > RFC 1149 Compliant. > > ""J-B"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Team, > > I have the following problem: > > > > Our network has 10 sites, I am in the process of readdressing current > > network. I have setup secondary ip address on every site, At the present > > time I am setting up a wk2000 dhcp/win server in one site. The problem is > > that I am not able to obtain ip address from the DHCP server via the WAN, > it > > works fine in the site where it is locate. The layout is the following: > > > > Hub site > > > > interface Ethernet0 > > ip address 192.168.13.1 255.255.255.0 secondary > > ip address 192.168.1.1 255.255.255.0 > > ip helper-address 192.168.12.17 > > ip directed-broadcast > > no cdp enable > > > > interface Serial0 > > no ip address > > ip directed-broadcast > > encapsulation frame-relay IETF > > no ip mroute-cache > > frame-relay lmi-type ansi > > > > interface Serial0.3 point-to-point > > description Spoke site > > bandwidth 384 > > ip unnumbered Ethernet0 > > ip helper-address 192.168.12.17 > > ip directed-broadcast > > frame-relay interface-dlci 26 > > > > Spoke site > > > > interface Ethernet0 > > ip address 192.168.12.1 255.255.255.0 secondary > > ip address 192.168.2.1 255.255.255.0 > > > > interface Serial0 > > no ip address > > encapsulation frame-relay IETF > > no fair-queue > > frame-relay lmi-type ansi > > ! > > interface Serial0.1 point-to-point > > description connection to Hub > > ip unnumbered Ethernet0 > > bandwidth 384 > > frame-relay interface-dlci 16 > > ! > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > Be aware that I have not problem pinging to the DHCP server from the Hub > > site. > > > > Team, what I am doing wrong here...HELP > > > > > > Thanks (nothing can replace experiencewo) > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35535&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35533]
As a test, statically configure a client to be on the 192.168.2.0 network with correct gateway info, mask, etc. Then 1, try pinging the server and see if that works, and two, change config to dhcp then. What range is the dhcp server supposed to be passing out, the secondary addresses range, because it won't work either. The DHCP server must pass out the primary address range because that's where the packet is coming from. -- RFC 1149 Compliant. ""J-B"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Well the clients have not ip address, what we are doing is remove all ip > address from the clients and enable DHCP > ""Steven A. Ridder"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > I bet the clients are on the new secondary networks? Is that true, > because > > if so, ip helper only works on the primary interface's address and not on > > the clients on the secondary network. It won't pick up the secondary > > networks broadcasts. > > > > -- > > RFC 1149 Compliant. > > > > ""J-B"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Team, > > > I have the following problem: > > > > > > Our network has 10 sites, I am in the process of readdressing current > > > network. I have setup secondary ip address on every site, At the present > > > time I am setting up a wk2000 dhcp/win server in one site. The problem > is > > > that I am not able to obtain ip address from the DHCP server via the > WAN, > > it > > > works fine in the site where it is locate. The layout is the following: > > > > > > Hub site > > > > > > interface Ethernet0 > > > ip address 192.168.13.1 255.255.255.0 secondary > > > ip address 192.168.1.1 255.255.255.0 > > > ip helper-address 192.168.12.17 > > > ip directed-broadcast > > > no cdp enable > > > > > > interface Serial0 > > > no ip address > > > ip directed-broadcast > > > encapsulation frame-relay IETF > > > no ip mroute-cache > > > frame-relay lmi-type ansi > > > > > > interface Serial0.3 point-to-point > > > description Spoke site > > > bandwidth 384 > > > ip unnumbered Ethernet0 > > > ip helper-address 192.168.12.17 > > > ip directed-broadcast > > > frame-relay interface-dlci 26 > > > > > > Spoke site > > > > > > interface Ethernet0 > > > ip address 192.168.12.1 255.255.255.0 secondary > > > ip address 192.168.2.1 255.255.255.0 > > > > > > interface Serial0 > > > no ip address > > > encapsulation frame-relay IETF > > > no fair-queue > > > frame-relay lmi-type ansi > > > ! > > > interface Serial0.1 point-to-point > > > description connection to Hub > > > ip unnumbered Ethernet0 > > > bandwidth 384 > > > frame-relay interface-dlci 16 > > > ! > > > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > > > Be aware that I have not problem pinging to the DHCP server from the Hub > > > site. > > > > > > Team, what I am doing wrong here...HELP > > > > > > > > > Thanks (nothing can replace experiencewo) > > > > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35538&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35539]
do you have a scope setup in dhcp server for that range? -Original Message- From: J-B [mailto:[EMAIL PROTECTED]] Sent: Friday, February 15, 2002 1:22 PM To: [EMAIL PROTECTED] Subject: Secondary ip address and ip helper-address HELPP [7:35532] Team, I have the following problem: Our network has 10 sites, I am in the process of readdressing current network. I have setup secondary ip address on every site, At the present time I am setting up a wk2000 dhcp/win server in one site. The problem is that I am not able to obtain ip address from the DHCP server via the WAN, it works fine in the site where it is locate. The layout is the following: Hub site interface Ethernet0 ip address 192.168.13.1 255.255.255.0 secondary ip address 192.168.1.1 255.255.255.0 ip helper-address 192.168.12.17 ip directed-broadcast no cdp enable interface Serial0 no ip address ip directed-broadcast encapsulation frame-relay IETF no ip mroute-cache frame-relay lmi-type ansi interface Serial0.3 point-to-point description Spoke site bandwidth 384 ip unnumbered Ethernet0 ip helper-address 192.168.12.17 ip directed-broadcast frame-relay interface-dlci 26 Spoke site interface Ethernet0 ip address 192.168.12.1 255.255.255.0 secondary ip address 192.168.2.1 255.255.255.0 interface Serial0 no ip address encapsulation frame-relay IETF no fair-queue frame-relay lmi-type ansi ! interface Serial0.1 point-to-point description connection to Hub ip unnumbered Ethernet0 bandwidth 384 frame-relay interface-dlci 16 ! The ip address of the DHCP sever is 192.168.12.17 Be aware that I have not problem pinging to the DHCP server from the Hub site. Team, what I am doing wrong here...HELP Thanks (nothing can replace experiencewo) JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35539&t=35539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35533]
I have done what you just mentioned(everything works except DHCP), the range that needs to be pass out is the new range which is related to the new ip secondary address. The user in Hub site(current ip layout is 192.168.1.0) should get an ip address for the new layout(192.168.13.0) ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > As a test, statically configure a client to be on the 192.168.2.0 network > with correct gateway info, mask, etc. Then 1, try pinging the server and see > if that works, and two, change config to dhcp then. What range is the dhcp > server supposed to be passing out, the secondary addresses range, because it > won't work either. The DHCP server must pass out the primary address range > because that's where the packet is coming from. > > -- > RFC 1149 Compliant. > > ""J-B"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Well the clients have not ip address, what we are doing is remove all ip > > address from the clients and enable DHCP > > ""Steven A. Ridder"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > I bet the clients are on the new secondary networks? Is that true, > > because > > > if so, ip helper only works on the primary interface's address and not > on > > > the clients on the secondary network. It won't pick up the secondary > > > networks broadcasts. > > > > > > -- > > > RFC 1149 Compliant. > > > > > > ""J-B"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Team, > > > > I have the following problem: > > > > > > > > Our network has 10 sites, I am in the process of readdressing current > > > > network. I have setup secondary ip address on every site, At the > present > > > > time I am setting up a wk2000 dhcp/win server in one site. The problem > > is > > > > that I am not able to obtain ip address from the DHCP server via the > > WAN, > > > it > > > > works fine in the site where it is locate. The layout is the > following: > > > > > > > > Hub site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.13.1 255.255.255.0 secondary > > > > ip address 192.168.1.1 255.255.255.0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > no cdp enable > > > > > > > > interface Serial0 > > > > no ip address > > > > ip directed-broadcast > > > > encapsulation frame-relay IETF > > > > no ip mroute-cache > > > > frame-relay lmi-type ansi > > > > > > > > interface Serial0.3 point-to-point > > > > description Spoke site > > > > bandwidth 384 > > > > ip unnumbered Ethernet0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > frame-relay interface-dlci 26 > > > > > > > > Spoke site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.12.1 255.255.255.0 secondary > > > > ip address 192.168.2.1 255.255.255.0 > > > > > > > > interface Serial0 > > > > no ip address > > > > encapsulation frame-relay IETF > > > > no fair-queue > > > > frame-relay lmi-type ansi > > > > ! > > > > interface Serial0.1 point-to-point > > > > description connection to Hub > > > > ip unnumbered Ethernet0 > > > > bandwidth 384 > > > > frame-relay interface-dlci 16 > > > > ! > > > > > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > > > > > Be aware that I have not problem pinging to the DHCP server from the > Hub > > > > site. > > > > > > > > Team, what I am doing wrong > here...HELP > > > > > > > > > > > > Thanks (nothing can replace experiencewo) > > > > > > > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35542&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35533]
The problem is that the router sends the "helped dhcp packet" to the dhcp server with a source "giaadr" of the routers primary address. The dhcp server receives the packet, sees the source is in 192.168.2.0 range and tries to pass out an address in that range from it's database. I'm betting that it doesn't have a scope for the 192.169.2.0 range, so it fails. I'd swap the primary and secondary addresses on all the routers if you can and it will work. -- RFC 1149 Compliant. ""J-B"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I have done what you just mentioned(everything works except DHCP), the range > that needs to be pass out is the new range which is related to the new ip > secondary address. The user in Hub site(current ip layout is 192.168.1.0) > should get an ip address for the new layout(192.168.13.0) > ""Steven A. Ridder"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > As a test, statically configure a client to be on the 192.168.2.0 network > > with correct gateway info, mask, etc. Then 1, try pinging the server and > see > > if that works, and two, change config to dhcp then. What range is the > dhcp > > server supposed to be passing out, the secondary addresses range, because > it > > won't work either. The DHCP server must pass out the primary address > range > > because that's where the packet is coming from. > > > > -- > > RFC 1149 Compliant. > > > > ""J-B"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Well the clients have not ip address, what we are doing is remove all ip > > > address from the clients and enable DHCP > > > ""Steven A. Ridder"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > I bet the clients are on the new secondary networks? Is that true, > > > because > > > > if so, ip helper only works on the primary interface's address and not > > on > > > > the clients on the secondary network. It won't pick up the secondary > > > > networks broadcasts. > > > > > > > > -- > > > > RFC 1149 Compliant. > > > > > > > > ""J-B"" wrote in message > > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > > Team, > > > > > I have the following problem: > > > > > > > > > > Our network has 10 sites, I am in the process of readdressing > current > > > > > network. I have setup secondary ip address on every site, At the > > present > > > > > time I am setting up a wk2000 dhcp/win server in one site. The > problem > > > is > > > > > that I am not able to obtain ip address from the DHCP server via the > > > WAN, > > > > it > > > > > works fine in the site where it is locate. The layout is the > > following: > > > > > > > > > > Hub site > > > > > > > > > > interface Ethernet0 > > > > > ip address 192.168.13.1 255.255.255.0 secondary > > > > > ip address 192.168.1.1 255.255.255.0 > > > > > ip helper-address 192.168.12.17 > > > > > ip directed-broadcast > > > > > no cdp enable > > > > > > > > > > interface Serial0 > > > > > no ip address > > > > > ip directed-broadcast > > > > > encapsulation frame-relay IETF > > > > > no ip mroute-cache > > > > > frame-relay lmi-type ansi > > > > > > > > > > interface Serial0.3 point-to-point > > > > > description Spoke site > > > > > bandwidth 384 > > > > > ip unnumbered Ethernet0 > > > > > ip helper-address 192.168.12.17 > > > > > ip directed-broadcast > > > > > frame-relay interface-dlci 26 > > > > > > > > > > Spoke site > > > > > > > > > > interface Ethernet0 > > > > > ip address 192.168.12.1 255.255.255.0 secondary > > > > > ip address 192.168.2.1 255.255.255.0 > > > > > > > > > > interface Serial0 > > > > > no ip address > > > > > encapsulation frame-relay IETF > > > > > no fair-queue > > > > > frame-relay lmi-type ansi > > > > > ! > > > > > interface Serial0.1 point-to-point > > > > > description connection to Hub > > > > > ip unnumbered Ethernet0 > > > > > bandwidth 384 > > > > > frame-relay interface-dlci 16 > > > > > ! > > > > > > > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > > > > > > > Be aware that I have not problem pinging to the DHCP server from the > > Hub > > > > > site. > > > > > > > > > > Team, what I am doing wrong > > here...HELP > > > > > > > > > > > > > > > Thanks (nothing can replace experiencewo) > > > > > > > > > > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35543&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35533]
i guess if you wanted to bounce the interface by flip flopping (please note my english skills) the primary and secondary addresses and see what happens..unless of course this is a major production router -Original Message- From: J-B [mailto:[EMAIL PROTECTED]] Sent: Friday, February 15, 2002 1:50 PM To: [EMAIL PROTECTED] Subject: Re: Secondary ip address and ip helper-address [7:35533] I have done what you just mentioned(everything works except DHCP), the range that needs to be pass out is the new range which is related to the new ip secondary address. The user in Hub site(current ip layout is 192.168.1.0) should get an ip address for the new layout(192.168.13.0) ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > As a test, statically configure a client to be on the 192.168.2.0 network > with correct gateway info, mask, etc. Then 1, try pinging the server and see > if that works, and two, change config to dhcp then. What range is the dhcp > server supposed to be passing out, the secondary addresses range, because it > won't work either. The DHCP server must pass out the primary address range > because that's where the packet is coming from. > > -- > RFC 1149 Compliant. > > ""J-B"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Well the clients have not ip address, what we are doing is remove all ip > > address from the clients and enable DHCP > > ""Steven A. Ridder"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > I bet the clients are on the new secondary networks? Is that true, > > because > > > if so, ip helper only works on the primary interface's address and not > on > > > the clients on the secondary network. It won't pick up the secondary > > > networks broadcasts. > > > > > > -- > > > RFC 1149 Compliant. > > > > > > ""J-B"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Team, > > > > I have the following problem: > > > > > > > > Our network has 10 sites, I am in the process of readdressing current > > > > network. I have setup secondary ip address on every site, At the > present > > > > time I am setting up a wk2000 dhcp/win server in one site. The problem > > is > > > > that I am not able to obtain ip address from the DHCP server via the > > WAN, > > > it > > > > works fine in the site where it is locate. The layout is the > following: > > > > > > > > Hub site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.13.1 255.255.255.0 secondary > > > > ip address 192.168.1.1 255.255.255.0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > no cdp enable > > > > > > > > interface Serial0 > > > > no ip address > > > > ip directed-broadcast > > > > encapsulation frame-relay IETF > > > > no ip mroute-cache > > > > frame-relay lmi-type ansi > > > > > > > > interface Serial0.3 point-to-point > > > > description Spoke site > > > > bandwidth 384 > > > > ip unnumbered Ethernet0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > frame-relay interface-dlci 26 > > > > > > > > Spoke site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.12.1 255.255.255.0 secondary > > > > ip address 192.168.2.1 255.255.255.0 > > > > > > > > interface Serial0 > > > > no ip address > > > > encapsulation frame-relay IETF > > > > no fair-queue > > > > frame-relay lmi-type ansi > > > > ! > > > > interface Serial0.1 point-to-point > > > > description connection to Hub > > > > ip unnumbered Ethernet0 > > > > bandwidth 384 > > > > frame-relay interface-dlci 16 > > > > ! > > > > > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > > > > > Be aware that I have not problem pinging to the DHCP server from the > Hub > > > > site. > > > > > > > > Team, what I am doing wrong > here...HELP > > > > > > > > > > > > Thanks (nothing can replace experiencewo) > > > > > > > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35545&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35533]
flip-flop your primary and secondary addresses on the hub router: interface Ethernet0 ip address 192.168.1.1 255.255.255.0 secondary ip address 192.168.13.1 255.255.255.0 ip helper-address 192.168.12.17 This will let the old 192.168.1.x addresses age-out gracefully while assigning new addresses from the 192.168.13.x range. I'm assuming here that your DHCP server is configured to pass-out addresses from 192.168.13.x. You were having the problem because the router "helpers" the DHCP request using its primary address -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of J-B Sent: Friday, February 15, 2002 1:50 PM To: [EMAIL PROTECTED] Subject: Re: Secondary ip address and ip helper-address [7:35533] I have done what you just mentioned(everything works except DHCP), the range that needs to be pass out is the new range which is related to the new ip secondary address. The user in Hub site(current ip layout is 192.168.1.0) should get an ip address for the new layout(192.168.13.0) ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > As a test, statically configure a client to be on the 192.168.2.0 network > with correct gateway info, mask, etc. Then 1, try pinging the server and see > if that works, and two, change config to dhcp then. What range is the dhcp > server supposed to be passing out, the secondary addresses range, because it > won't work either. The DHCP server must pass out the primary address range > because that's where the packet is coming from. > > -- > RFC 1149 Compliant. > > ""J-B"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Well the clients have not ip address, what we are doing is remove all ip > > address from the clients and enable DHCP > > ""Steven A. Ridder"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > I bet the clients are on the new secondary networks? Is that true, > > because > > > if so, ip helper only works on the primary interface's address and not > on > > > the clients on the secondary network. It won't pick up the secondary > > > networks broadcasts. > > > > > > -- > > > RFC 1149 Compliant. > > > > > > ""J-B"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > Team, > > > > I have the following problem: > > > > > > > > Our network has 10 sites, I am in the process of readdressing current > > > > network. I have setup secondary ip address on every site, At the > present > > > > time I am setting up a wk2000 dhcp/win server in one site. The problem > > is > > > > that I am not able to obtain ip address from the DHCP server via the > > WAN, > > > it > > > > works fine in the site where it is locate. The layout is the > following: > > > > > > > > Hub site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.13.1 255.255.255.0 secondary > > > > ip address 192.168.1.1 255.255.255.0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > no cdp enable > > > > > > > > interface Serial0 > > > > no ip address > > > > ip directed-broadcast > > > > encapsulation frame-relay IETF > > > > no ip mroute-cache > > > > frame-relay lmi-type ansi > > > > > > > > interface Serial0.3 point-to-point > > > > description Spoke site > > > > bandwidth 384 > > > > ip unnumbered Ethernet0 > > > > ip helper-address 192.168.12.17 > > > > ip directed-broadcast > > > > frame-relay interface-dlci 26 > > > > > > > > Spoke site > > > > > > > > interface Ethernet0 > > > > ip address 192.168.12.1 255.255.255.0 secondary > > > > ip address 192.168.2.1 255.255.255.0 > > > > > > > > interface Serial0 > > > > no ip address > > > > encapsulation frame-relay IETF > > > > no fair-queue > > > > frame-relay lmi-type ansi > > > > ! > > > > interface Serial0.1 point-to-point > > > > description connection to Hub > > > > ip unnumbered Ethernet0 > > > > bandwidth 384 > > > > frame-relay interface-dlci 16 > > > > ! > > > > > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > > > > > Be aware that I have not problem pinging to the DHCP server from the > Hub > > > > site. > > > > > > > > Team, what I am doing wrong > here...HELP > > > > > > > > > > > > Thanks (nothing can replace experiencewo) > > > > > > > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35548&t=35533 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35539]
Plus, upon re-reading your post, I don't see an IP helper setup on the eth0 interface on the spoke router just like you have on the hub router. You need to add that. The point of my previous post was to highlight the fact that you need to make sure that the primary IP on the eth0 on the spoke router be in the same subnet with the IPs you want to hand out via DHCP. AFAIK, it's not possible to service multiple subnets simultaneously on a single interface via IP-Helper. (i.e. I don't think it's possible service any secondary IP subnets on eth0 at the spoke site because the IP-Helper uses the primary eth0 IP as the source address for the DHCP directed request) Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35577&t=35539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35583]
Are you trying to pull IP's in the range specified by the secondary address? If so, try reversing the primary and secondary addresses. If I remember correctly, the Ethernet interface will show as coming from the primary and the DHCP server will not see a scope for this range, Only for the secondary. No match=No address. Larry -Original Message- From: J-B [mailto:[EMAIL PROTECTED]] Sent: Friday, February 15, 2002 2:22 PM To: [EMAIL PROTECTED] Subject: Secondary ip address and ip helper-address HELPP [7:35532] Team, I have the following problem: Our network has 10 sites, I am in the process of readdressing current network. I have setup secondary ip address on every site, At the present time I am setting up a wk2000 dhcp/win server in one site. The problem is that I am not able to obtain ip address from the DHCP server via the WAN, it works fine in the site where it is locate. The layout is the following: Hub site interface Ethernet0 ip address 192.168.13.1 255.255.255.0 secondary ip address 192.168.1.1 255.255.255.0 ip helper-address 192.168.12.17 ip directed-broadcast no cdp enable interface Serial0 no ip address ip directed-broadcast encapsulation frame-relay IETF no ip mroute-cache frame-relay lmi-type ansi interface Serial0.3 point-to-point description Spoke site bandwidth 384 ip unnumbered Ethernet0 ip helper-address 192.168.12.17 ip directed-broadcast frame-relay interface-dlci 26 Spoke site interface Ethernet0 ip address 192.168.12.1 255.255.255.0 secondary ip address 192.168.2.1 255.255.255.0 interface Serial0 no ip address encapsulation frame-relay IETF no fair-queue frame-relay lmi-type ansi ! interface Serial0.1 point-to-point description connection to Hub ip unnumbered Ethernet0 bandwidth 384 frame-relay interface-dlci 16 ! The ip address of the DHCP sever is 192.168.12.17 Be aware that I have not problem pinging to the DHCP server from the Hub site. Team, what I am doing wrong here...HELP Thanks (nothing can replace experiencewo) JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35583&t=35583 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35601]
Make sure your Microcrap server is using a superscope to encompass both your DHCP scopes. ""J-B"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Team, > I have the following problem: > > Our network has 10 sites, I am in the process of readdressing current > network. I have setup secondary ip address on every site, At the present > time I am setting up a wk2000 dhcp/win server in one site. The problem is > that I am not able to obtain ip address from the DHCP server via the WAN, it > works fine in the site where it is locate. The layout is the following: > > Hub site > > interface Ethernet0 > ip address 192.168.13.1 255.255.255.0 secondary > ip address 192.168.1.1 255.255.255.0 > ip helper-address 192.168.12.17 > ip directed-broadcast > no cdp enable > > interface Serial0 > no ip address > ip directed-broadcast > encapsulation frame-relay IETF > no ip mroute-cache > frame-relay lmi-type ansi > > interface Serial0.3 point-to-point > description Spoke site > bandwidth 384 > ip unnumbered Ethernet0 > ip helper-address 192.168.12.17 > ip directed-broadcast > frame-relay interface-dlci 26 > > Spoke site > > interface Ethernet0 > ip address 192.168.12.1 255.255.255.0 secondary > ip address 192.168.2.1 255.255.255.0 > > interface Serial0 > no ip address > encapsulation frame-relay IETF > no fair-queue > frame-relay lmi-type ansi > ! > interface Serial0.1 point-to-point > description connection to Hub > ip unnumbered Ethernet0 > bandwidth 384 > frame-relay interface-dlci 16 > ! > > The ip address of the DHCP sever is 192.168.12.17 > > Be aware that I have not problem pinging to the DHCP server from the Hub > site. > > Team, what I am doing wrong here...HELP > > > Thanks (nothing can replace experiencewo) > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35601&t=35601 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35539]
Just a clarification. It is possible to have multiple subnets on an interface and configure the DHCP server to assign IPs to any of these scopes. No router address flip-flopping or other machinations are required or needed. As has been posted, the primary IP address on the interface is *usually* (see details below) the giaddr placed into the DHCP packet by the relay agent (router). Lets assume that the interface doing the IP helpering has four subnets: P (the primary) and S1, S2, and S3. On any reasonable DHCP server, one can configure the secondary subnets to be "secondaries" to the primary in the DHCP config. So when one configures their DHCP server, they define the primary subnet information for P, and then define the information for S1, S2, and S3. One then ties these all together by making S1 a "secondary" of P on the DHCP server. Ditto for S2 and S3. The manner in which one makes S1, S2, and S3 secondaries is DHCP server dependent. If you have CNR and want to make S1 a secondary to P do the following: 1) Define the scope information for P, S1, S2, and S3. This would entail defining the range of address to hand out for each scope, the policy (DHCP attributes, selection tags, etc.) 2) Using the GUI, select the S1 subnet, then "properties" and then the "advanced" tab. Half way down, there a selection box to make this scope a secondary. Select this box, and when you do this, you can then select the primary for this scope. Select P. Note, this can also be done using the CLI. I believe the attribute name is "primary-scope" (or something close). Using the CLI, for scope S1, set its "primary-scope" attribute to the scope name you defined for subnet P. Once you;ve done this, when a packet arrives at the DHCP server with a giaddr of P, the DHCP server now knows that P and S1, S2, and S3 are all related. The DHCP server uses this, and any configurations the operator has provided to help select the appropriate scope (subnet) and thus IP for this device. Doing the above is very common practice in the cable industry. On any CMTS cable inteface, cable companies will have customer IPs subnets (for PCs) and subnets for cable modems. CPEs will be assigned globally routeable addresses (net24, net12, etc). and the cable modems will be assigned net10 addresses. The structure define above is used-- one of these subnets will be the primary on the CMTS interface and the rest will be secondaries. All are tied together on the DHCP server via the "priamry-secondary" logic described above. Cable operators configure the DHCP server logic to identify a DHCP request from a modem and map it to one of the subnet(s) on the interface created for modems. Ditto for PCs. Note, above I indicated that the primary address is *usually* the giaddr. Two caveats to this: * Cisco changed how the relay helpering works in some IOS revs-- in some 11.x or 12.x revs, the giaddr can cycle through all gateway addresses assigned on the helpering interface. That is, when a packet gets helpered, the router will initially insert the P address as the giaddr. If the DHCP server does not respond, and the router has helpered 3-4 DISCOVERs on behalf of a source, the 5-8th DHCP DISCOVER packets will get helpered using a giaddr of S1. This repeats 3-4 times, and if no DHCP response is received, S2 is used as the next giaddr. Note, the router maintains the state for each source so a new device will get helpered initially with P as the giaddr. (I don't recall when cisco enabled this cycling feature to be the defualt behavior. I believe they changed the default behavior back to only using "P" as the giaddr (I don't recall the IOS rev). However, I believe they've added a new know so that one can enable this "cycling" "feature" in current IOS revs. * On cable infrastructure gear (CMTSs), there are extra knobs to customize what value is inserted into the giaddr. One can configure the CMTS to always use the "P" address as the giaddr or to perform the cycling (described above). Michael Williams wrote: > > Plus, upon re-reading your post, I don't see an IP helper setup on the eth0 > interface on the spoke router just like you have on the hub router. You > need to add that. > > The point of my previous post was to highlight the fact that you need to > make sure that the primary IP on the eth0 on the spoke router be in the same > subnet with the IPs you want to hand out via DHCP. AFAIK, it's not possible > to service multiple subnets simultaneously on a single interface via > IP-Helper. (i.e. I don't think it's possible service any secondary IP > subnets on eth0 at the spoke site because the IP-Helper uses the primary > eth0 IP as the source address for the DHCP directed request) > > Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35602&t=35539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report
Re: Secondary ip address and ip helper-address [7:35539]
Comments inline.. > Once you;ve done this, when a packet arrives at the DHCP server > with a > giaddr of > P, the DHCP server now knows that P and S1, S2, and S3 are all > related. > The DHCP > server uses this, and any configurations the operator has > provided > to help select the appropriate scope (subnet) and thus IP for > this > device. I understand the logic of tying the secondary scopes to the primary at ehe DHCP side, however if the giaddr always reflects the primary subnet, how the the DHCP server ever know to hand out addrs from the other secondary scopes? > Note, above I indicated that the primary address is *usually* > the > giaddr. > Two caveats to this: > > * Cisco changed how the relay helpering works in some IOS > revs-- in some > 11.x > or 12.x revs, the giaddr can cycle through all gateway addresses > assigned on the > helpering interface. That is, when a packet gets helpered, the > router > will initially > insert the P address as the giaddr. If the DHCP server does not > respond, and > the router has helpered 3-4 DISCOVERs on behalf of a source, > the 5-8th > DHCP DISCOVER > packets will get helpered using a giaddr of S1. This repeats > 3-4 times, > and if no > DHCP response is received, S2 is used as the next giaddr. This "feature" you describe sounds pretty worthless. If the giaddr is always from P, and rotates through S1, S2, S3, etc when the DHCP server doesn't respond, then unless your DHCP server is down or all IPs have been allotted for subnet P, then the DHCP request will always result in an IP from the scope for P. Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35612&t=35539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35601]
One must be wary of using secondary addresses. As has been discussed here many a time, in many a context, secondary addressing on routers is problematic. Adjacencies in various routing protocols do not form. Routes do not get exchanged. In general, the router will use the primary address as it's source for lots of things, including DCHP forwarding. one solution to the particular problem might be to use the router itself as the local DHCP server. Chuck ""GAHellinger"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Make sure your Microcrap server is using a superscope to encompass both your > DHCP scopes. > > > ""J-B"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Team, > > I have the following problem: > > > > Our network has 10 sites, I am in the process of readdressing current > > network. I have setup secondary ip address on every site, At the present > > time I am setting up a wk2000 dhcp/win server in one site. The problem is > > that I am not able to obtain ip address from the DHCP server via the WAN, > it > > works fine in the site where it is locate. The layout is the following: > > > > Hub site > > > > interface Ethernet0 > > ip address 192.168.13.1 255.255.255.0 secondary > > ip address 192.168.1.1 255.255.255.0 > > ip helper-address 192.168.12.17 > > ip directed-broadcast > > no cdp enable > > > > interface Serial0 > > no ip address > > ip directed-broadcast > > encapsulation frame-relay IETF > > no ip mroute-cache > > frame-relay lmi-type ansi > > > > interface Serial0.3 point-to-point > > description Spoke site > > bandwidth 384 > > ip unnumbered Ethernet0 > > ip helper-address 192.168.12.17 > > ip directed-broadcast > > frame-relay interface-dlci 26 > > > > Spoke site > > > > interface Ethernet0 > > ip address 192.168.12.1 255.255.255.0 secondary > > ip address 192.168.2.1 255.255.255.0 > > > > interface Serial0 > > no ip address > > encapsulation frame-relay IETF > > no fair-queue > > frame-relay lmi-type ansi > > ! > > interface Serial0.1 point-to-point > > description connection to Hub > > ip unnumbered Ethernet0 > > bandwidth 384 > > frame-relay interface-dlci 16 > > ! > > > > The ip address of the DHCP sever is 192.168.12.17 > > > > Be aware that I have not problem pinging to the DHCP server from the Hub > > site. > > > > Team, what I am doing wrong here...HELP > > > > > > Thanks (nothing can replace experiencewo) > > > > > > JB Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35615&t=35601 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Secondary ip address and ip helper-address [7:35539]
Hi Mike, Responses inline: > I understand the logic of tying the secondary scopes to the primary at ehe > DHCP side, however if the giaddr always reflects the primary subnet, how the > the DHCP server ever know to hand out addrs from the other secondary scopes? On the DHCP server, one configures the S1, S2, and S3 scopes to be "related" to the P scope. The DHCP server then knows there are four different subnets on this interface are related through P. When the DHCP server receives a DHCP DISCOVER with P as the giaddr, the above linkage indicates to the DHCP server that four subnets are on the same router interface. Without any additional logic, the DHCP server could randonly pick a free IP address from any of these four scopes, and send the selected IP in the DHCP OFFER. Note, that the DHCP server will send the DHCP OFFER (and ACK) to the giaddr IP (P). The router receives the DHCP packet, knows what interface it's asociated with (P), and forwards out the inteface accordingly. Also note that the DHCP server will likely also return other DHCP information in the OFFER including default gateway, subnet mask, DNS server IPs and domain information. The default gateway and subnet mask will be specific to the scope from which the IP was selected. Now, one could configure extra smarts into the DHCP server so that based on the device making the DHCP request, the DHCP server could assign the device an address out of one specific scope. Some devices will use DHCP Option 60 to inform the DHCP server of its device type. The DHCP server can be configured to use this information to help it select which of the scopes on the interface are applicable for this device. There are other mechanisms that can also be used by the DHCP server to help determine how to select which scope the DHCP request should be mapped to (device MAC address or OUI, DHCP Option 82, etc.) > This "feature" you describe sounds pretty worthless. If the giaddr is > always from P, and rotates through S1, S2, S3, etc when the DHCP server > doesn't respond, then unless your DHCP server is down or all IPs have been > allotted for subnet P, then the DHCP request will always result in an IP > from the scope for P. I think the idea for this cycling feature is as follows: If one wanted to assign multiple subnets onto an interface and these subnets are configured to have their IPs assigned via DHCP, then you have the problem discussed in this thread. I expect that there are some off-the-shelf DHCP servers which didn't have the ability to logically associate multiple subnets together. That is, the DHCP server had the limitation that each scope had to appear as if it was on its own interface. In this sort of environment, the only way for the DHCP server to match any of the secondary subnets was if it saw a giaddr from one of these secondary subnets. If the router only ever inserted the P address in the giaddr, none of the other scopes would ever be matched. This cycling approach causes the giaddr to change and rotate through all the subnets on the interface. As mentioned before, cisco now has a command which allows one to specify the DHCP relay behavior (ie always use the primary address or cycle through all subnets on the interface). This command is called "ip dhcp smart-relay". http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122sup/122csum/csum1/122csip1/1sfdhcp.htm#xtocid1563023 So in answer to the original poster's question, this command could be used to solve his/her problem. Of course, one needs to be running the right IOS rev and this approach will take 10s of seconds or minutes for the device to come online (as the DHCP cycling happens). Configuring the interaces to be related on the DHCP server is really that way to go (IMO). Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35626&t=35539 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address [7:35533]
Looking at the config, I do not understand why you have the ip helper address configured under the serial interface. It should be under the ethernet interface where packets are getting in from the Land network. Try putting the Ip helpler address under the Ethernet no the serial interface. >From: "Wright, Jeremy" >Reply-To: "Wright, Jeremy" >To: [EMAIL PROTECTED] >Subject: RE: Secondary ip address and ip helper-address [7:35533] >Date: Fri, 15 Feb 2002 15:15:28 -0500 > >i guess if you wanted to bounce the interface by flip flopping (please note >my english skills) the primary and secondary addresses and see what >happens..unless of course this is a major production router > >-Original Message- >From: J-B [mailto:[EMAIL PROTECTED]] >Sent: Friday, February 15, 2002 1:50 PM >To: [EMAIL PROTECTED] >Subject: Re: Secondary ip address and ip helper-address [7:35533] > > >I have done what you just mentioned(everything works except DHCP), the >range >that needs to be pass out is the new range which is related to the new ip >secondary address. The user in Hub site(current ip layout is 192.168.1.0) >should get an ip address for the new layout(192.168.13.0) >""Steven A. Ridder"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > As a test, statically configure a client to be on the 192.168.2.0 >network > > with correct gateway info, mask, etc. Then 1, try pinging the server and >see > > if that works, and two, change config to dhcp then. What range is the >dhcp > > server supposed to be passing out, the secondary addresses range, >because >it > > won't work either. The DHCP server must pass out the primary address >range > > because that's where the packet is coming from. > > > > -- > > RFC 1149 Compliant. > > > > ""J-B"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Well the clients have not ip address, what we are doing is remove all >ip > > > address from the clients and enable DHCP > > > ""Steven A. Ridder"" wrote in message > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > I bet the clients are on the new secondary networks? Is that true, > > > because > > > > if so, ip helper only works on the primary interface's address and >not > > on > > > > the clients on the secondary network. It won't pick up the >secondary > > > > networks broadcasts. > > > > > > > > -- > > > > RFC 1149 Compliant. > > > > > > > > ""J-B"" wrote in message > > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > > Team, > > > > > I have the following problem: > > > > > > > > > > Our network has 10 sites, I am in the process of readdressing >current > > > > > network. I have setup secondary ip address on every site, At the > > present > > > > > time I am setting up a wk2000 dhcp/win server in one site. The >problem > > > is > > > > > that I am not able to obtain ip address from the DHCP server via >the > > > WAN, > > > > it > > > > > works fine in the site where it is locate. The layout is the > > following: > > > > > > > > > > Hub site > > > > > > > > > > interface Ethernet0 > > > > > ip address 192.168.13.1 255.255.255.0 secondary > > > > > ip address 192.168.1.1 255.255.255.0 > > > > > ip helper-address 192.168.12.17 > > > > > ip directed-broadcast > > > > > no cdp enable > > > > > > > > > > interface Serial0 > > > > > no ip address > > > > > ip directed-broadcast > > > > > encapsulation frame-relay IETF > > > > > no ip mroute-cache > > > > > frame-relay lmi-type ansi > > > > > > > > > > interface Serial0.3 point-to-point > > > > > description Spoke site > > > > > bandwidth 384 > > > > > ip unnumbered Ethernet0 > > > > > ip helper-address 192.168.12.17 > > > > > ip directed-broadcast > > > > > frame-relay interface-dlci 26 > > > > > > > > > > Spoke site > > > > > > > > > > interface Ethernet0 > > > > > ip
Re: IP helper-address, domain browsing & N [7:36089]
I am going to venture a guess :- According to MS NT's static ports assignment, TCP: 42 is for WINS replication, perhaps by changing this statetment from ip nat inside source static 10.0.3.40 xxx.xxx.xxx.156 extendable to ip nat inside source static 10.0.3.40 42 xxx.xxx.xxx.156 42 extendable may solve the problem. However, according to MS two other ports are also used in WINS functions: TCP:135 for WINS Manager and TCP:137 for WINS Registration. Interest to know if this helps. ""Kurdziel Peter"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Does anyone know of any issues using the IP helper-address and domain > browsing while using NAT? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=36220&t=36089 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP helper-address, domain browsing & N [7:36089]
Is Nat on on the NJ router? If so, just Nat from CA only. -- RFC 1149 Compliant. ""Kurdziel Peter"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Does anyone know of any issues using the IP helper-address and domain > browsing while using NAT? > > > I have 2 locations, CA and NJ. > CA has a connection to the internet, NJ does not. CA and NJ are connected > via a point-to-point link via their serial insterfaces. With the help of > NATting NJ now is able to access the internet via the router in CA. > > My problem is that I need the servers at each location to replicate their > WINS databases. To try and solve this issues I added IP Helper-adress to the > serial point to point link on both side. If I remove the ip nat inside or > the ip nat outside command from either the fastethernet or the serail > interfaces I can broswe the domain and replicate the Wins database in either > location. But the NJ location does not have internet access. > > What do I need to do to enable both browsing to and from either location and > Internet access at both locations. > > > Here is a copy of my config from both locations. > > hostname California > ! > enable secret > ! > ! > ! > ! > ! > memory-size iomem 25 > ip subnet-zero > ! > ! > ! > ! > interface Serial0 > description Connection to ISP > ip address 10.0.10.1 255.255.255.252 > ip nat outside > no fair-queue > > > interface Serial1 > description point to point t1 to New Jersey > ip address 192.168.254.2 255.255.255.252 > ip helper-address 10.0.3.40 ***Server's IP in New Jersey* > no fair-queue > ! > interface FastEthernet0 > ip address 10.0.2.1 255.255.255.0 secondary > ip address xxx.xxx.xxx.155 255.255.255.248 > ip nat inside > speed auto > ! > ip nat pool local xxx.xxx.xxx.155 xxx.xxx.xxx.155 prefix-length 28 > ip nat inside source list 1 pool local overload > ip nat inside source static 10.0.3.40 xxx.xxx.xxx.156 extendable > ip classless > > ip route 0.0.0.0 0.0.0.0 serial0 > ip route 10.0.3.0 255.255.255.0 192.168.254.1 > ip route xxx.xxx.xxx.0 255.255.255.248 192.168.254.1 > > > no ip http server > ! > access-list 1 permit 10.0.2.0 0.0.0.255 > ! > line con 0 > password > line aux 0 > password > line vty 0 4 > password > ! > end > > > > hostname NewJersy > ! > enable secret > ! > ! > ! > ! > ! > memory-size iomem 25 > ip subnet-zero > ! > ! > ! > ! > interface Serial0 > description point to point t1 to California > ip address 192.168.254.1 255.255.255.252 > ip nat outside > no fair-queue > service-module t1 timeslots 1-24 > ! > interface FastEthernet0 > ip address 10.0.3.1 255.255.255.0 secondary > ip address xxx.xxx.xxx.46 255.255.255.248 > ip helper-address 10.0.2.9 ***Server's IP in California* > ip nat inside > speed auto > ! > ip nat pool local xxx.xxx.xxx.46 xxx.xxx.xxx.46 prefix-length 28 > ip nat inside source list 1 pool local overload > ip nat inside source static 10.0.3.40 xxx.xxx.xxx.45 extendable > ip classless > ip route 0.0.0.0 0.0.0.0 192.168.254.2 > no ip http server > ! > access-list 1 permit 10.0.3.0 0.0.0.255 > ! > line con 0 > password > line aux 0 > password > line vty 0 4 > password > ! > end Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=36204&t=36089 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP helper-address, domain browsing & N [7:36089]
"Dennis Bailey" wrote in message news:... > Hi Peter, > > Here is how I would change the configs: > > The helper-address would go on the fast ethernet interface of both routers > not the serial interface, > > Get rid of the secondary address and NAT on the NJ router--anything that the > NJ router does not have a route for will be forwarded to the CA router based > on the default route that you have on the NJ router--ip route 0.0.0.0 > 0.0.0.0 192.168.254.2 > > change the nat pool on the CA router to include the subnet or hosts from the > NJ sites that need to go to the Internet. > access-list 1 permit 10.0.2.0 0.0.0.255 > access-list 1 permit 10.0.3.0 0.0.0.255 > and add ip nat inside to interface serial 1 of the California router > > Dennis > > > ""Kurdziel Peter"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Does anyone know of any issues using the IP helper-address and domain > > browsing while using NAT? > > > > > > I have 2 locations, CA and NJ. > > CA has a connection to the internet, NJ does not. CA and NJ are connected > > via a point-to-point link via their serial insterfaces. With the help of > > NATting NJ now is able to access the internet via the router in CA. > > > > My problem is that I need the servers at each location to replicate their > > WINS databases. To try and solve this issues I added IP Helper-adress to > the > > serial point to point link on both side. If I remove the ip nat inside or > > the ip nat outside command from either the fastethernet or the serail > > interfaces I can broswe the domain and replicate the Wins database in > either > > location. But the NJ location does not have internet access. > > > > What do I need to do to enable both browsing to and from either location > and > > Internet access at both locations. > > > > > > Here is a copy of my config from both locations. > > > > hostname California > > ! > > enable secret > > ! > > ! > > ! > > ! > > ! > > memory-size iomem 25 > > ip subnet-zero > > ! > > ! > > ! > > ! > > interface Serial0 > > description Connection to ISP > > ip address 10.0.10.1 255.255.255.252 > > ip nat outside > > no fair-queue > > > > > > interface Serial1 > > description point to point t1 to New Jersey > > ip address 192.168.254.2 255.255.255.252 > > ip helper-address 10.0.3.40 ***Server's IP in New Jersey* > > no fair-queue > > ! > > interface FastEthernet0 > > ip address 10.0.2.1 255.255.255.0 secondary > > ip address xxx.xxx.xxx.155 255.255.255.248 > > ip nat inside > > speed auto > > ! > > ip nat pool local xxx.xxx.xxx.155 xxx.xxx.xxx.155 prefix-length 28 > > ip nat inside source list 1 pool local overload > > ip nat inside source static 10.0.3.40 xxx.xxx.xxx.156 extendable > > ip classless > > > > ip route 0.0.0.0 0.0.0.0 serial0 > > ip route 10.0.3.0 255.255.255.0 192.168.254.1 > > ip route xxx.xxx.xxx.0 255.255.255.248 192.168.254.1 > > > > > > no ip http server > > ! > > access-list 1 permit 10.0.2.0 0.0.0.255 > > ! > > line con 0 > > password > > line aux 0 > > password > > line vty 0 4 > > password > > ! > > end > > > > > > > > hostname NewJersy > > ! > > enable secret > > ! > > ! > > ! > > ! > > ! > > memory-size iomem 25 > > ip subnet-zero > > ! > > ! > > ! > > ! > > interface Serial0 > > description point to point t1 to California > > ip address 192.168.254.1 255.255.255.252 > > ip nat outside > > no fair-queue > > service-module t1 timeslots 1-24 > > ! > > interface FastEthernet0 > > ip address 10.0.3.1 255.255.255.0 secondary > > ip address xxx.xxx.xxx.46 255.255.255.248 > > ip helper-address 10.0.2.9 ***Server's IP in California* > > ip nat inside > > speed auto > > ! > > ip nat pool local xxx.xxx.xxx.46 xxx.xxx.xxx.46 prefix-length 28 > > ip nat inside source list 1 pool local overload > > ip nat inside source static 10.0.3.40 xxx.xxx.xxx.45 extendable > > ip classless > > ip route 0.0.0.0 0.0.0.0 192.168.254.2 > > no ip http server > > ! > > access-list 1 permit 10.0.3.0 0.0.0.255 > > ! > > line con 0 > > password > > line aux 0 > > password > > line vty 0 4 > > password > > ! > > end Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=36353&t=36089 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Ip helper address: which is the mac address? [7:44608]
Dear group, When my CPE comes up, it makes a dhcp request. The DHCP server is located on a different subnet .Between dhcp client (CPE) and dhcp server there is a router whit "ip helper-address" configured. My question is the following: if the DHCP server has to assign a specific IP address to a specific MAC address (CPE's MAC address) but there is a router between them, the DCHP will read the router MAC address...how does it works? Where DHCP will read the correct mac address before giving the right IP address? Thanks in advace, Teresa Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44608&t=44608 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
IP helper address with multiple vlans and 1 DHCP [7:351]
I know you guys talked about this earlier but how can I configured the router to limit exclusively an ip scope for a vlan when I only have one DHCP with multiple scopes and a switch with multiple vlans Ruddy CCNP, CCDA Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=351&t=351 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Secondary ip address and ip helper-address HELPPPP [7:35532]
I ran into this a while back. What's happening is when the router at the remote site is taking in the DHCP broadcast on eth0 and sending it to the DHCP server, it's using the primary address on the receiving interface (i.e. eth0 in your case) and sending that DHCP request on. When the DHCP server, it tries to allocate an IP in the same subnet (scope) with the IP of that request (again, which is the primary IP on the eth0 of the IP-helper router). In our case, our DHCP server wasn't handling the IP range that included tha primary IP on the eth0, so it wouldn't respond with an IP. Our solution was to swap the IPs. In your case that would be changing this on the spoke router: interface Ethernet0 ip address 192.168.12.1 255.255.255.0 secondary ip address 192.168.2.1 255.255.255.0 to this: interface Ethernet0 ip address 192.168.2.1 255.255.255.0 secondary ip address 192.168.12.1 255.255.255.0 This will allow the PCs in the 192.168.12.0 network to receive IPs from the DHCP server over the WAN. HTH, Mike W. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=35576&t=35532 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Ip helper address: which is the mac address? [7:44608]
TP wrote: > Where DHCP will read the correct mac address before giving the right IP > address? >From the CHADDR (Client Hardware ADDRess) field in the DHCP packet. Regards, Marco. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44609&t=44608 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Ip helper address: which is the mac address? [7:44608]
The DHCP server doesn't read the actually MAC address of the client PC. The DHCP client builds a DHCP request packet that includes the client's MAC address. The DHCP relay just passes that packet to the DHCP server, along with additional information (such as what subnet the request is coming from). Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44615&t=44608 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: IP helper address with multiple vlans and 1 DHCP [7:351]
Ruddy, If I understand the question (not necessarily a true statement): When the DHCP client (PC host) comes up it will send a broadcast for DHCP service, the vlan router will see the request packet and forward the request to the DHCP server using the IP helper address setup in the interface config. When the request is sent it indicates to the DHCP server which network this request is coming from and the DHCP will search the available scopes and select the scope that is for the requesting network. The server offer will be returned to the router which in turn sends it to the original requestor at which time the conversation becomes a unicast between the DHCP client and server. On the other hand if you are trying to reserver a specific IP within a scope for a specific PC host it must be setup on the DHCP server with the clients macaddr as a M-DHCP (manual dhcp). The conversation occurs as before except on a specific IP will be returned that satifies the macaddr -to- IP reservation setup on the DHCP server. Repost with clarifications if this has not help resolve the issue. ""Ruddy Cordero"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I know you guys talked about this earlier but how can I configured the router > to limit exclusively an ip scope for a vlan when I only have one DHCP with > multiple scopes and a switch with multiple vlans > > > Ruddy > CCNP, CCDA > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=412&t=351 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
