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
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
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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 you
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
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
>
>
ED]>
>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
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 ei
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
Su
es 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
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.groupstud
>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
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 i
t: 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?
>
>Ci
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 kno
>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 PR
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 a
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
rtain 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
&
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
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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
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 N
" <[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
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
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
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
"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 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
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
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
> abo
rized 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:
anik 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 "
/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
-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
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
on 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
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
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
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
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
P 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 Khalilu
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
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
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
holm <[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 (
g 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
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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
s 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
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
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 agre
L 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
hi
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 b
y 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 beca
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
me-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
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
> >
> > interfa
up 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
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
t; 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 loc
; > > > 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 s
, 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
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
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 ro
r 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 h
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
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
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 appropria
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
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 configure
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
OTECTED]...
> 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
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Is Nat on on the NJ router? If so, just Nat from CA only.
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""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
rom both locations.
> >
> > hostname California
> > !
> > enable secret
> > !
> > !
> > !
> > !
> > !
> > memory-size iomem 25
> > ip subnet-zero
> > !
> > !
> > !
> > !
> > interface Serial0
> >
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
ad
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=35
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 serve
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=4460
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 fro
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
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