RE: Simple Ip issue (need help) [7:62728]
i am not sure i understand your question, but from what u are saying, u want your central and client router to have the same IP address on their serial interfaces... why would u want that.. just having the IP address in the same subnet should do e.g 1.1.1.0/30 ... anyway, i think u may have a routing issue.. since 1.1.1.1/24 is directly connected on both routers, how would u tell the local router that 1.1.1.1/24 is on the other [destination router] side of the serial link, yet it knows its a local address...?.. please provide more information for the solution u need, and we can help work with something more scalable.. good luck.. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62730&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
Thanx, for instant reply. I am referring to have same ip on the serial interfaces of client router. Again I will show u my topolgy client-routerserver-router(isp) 2serial intf 2 serial intf serial 0 -ip add- 1.1.1.1 serial 0 ip add- 1.1.1.2 serial 1 -ip add- 1.1.1.1 serial 1 ip add- 1.1.1.2 I am using here duplicate ips on serial interfaces, is this connection correct or what design issues this has. We can use dulicate ip on serial with themselves but not duplicate with ethernet or loopback why ? any reason. -- Mark Tinka wrote: > > i am not sure i understand your question, but from what u are > saying, u want your central and client router to have the same > IP address on their serial interfaces... why would u want > that.. just having the IP address in the same subnet should do > e.g 1.1.1.0/30 ... > > anyway, i think u may have a routing issue.. since 1.1.1.1/24 > is directly connected on both routers, how would u tell the > local router that 1.1.1.1/24 is on the other [destination > router] side of the serial link, yet it knows its a local > address...?.. > > please provide more information for the solution u need, and we > can help work with something more scalable.. > > good luck.. - Hi All, I have very simple question, Can we use duplicate ips on serial interfaces among them seleves although we cannot use duplicate ip on serial with Ethernet(lan interface) or loopback interface. My topology is like this Client router server router(connected back to back) 2 interfaces 2 inetrfaces these routers connected back to back configuration int serial 0/0 encap hdlc ip address 1.1.1.1 255.255.255.0 int serial 0/1 ip address 1.1.1.1 255.255.255.0 encap hdlc now if all the two interfaces of serial even if given duplicate ip among themselves works fine. no error from cli .interfaces are up and i am able to ping remote side. The ques is that 1) Lan interface also was in different subnet but serial interface doesnot accept that ips as duplicate or of loopback 2)What Implication such have on my design ,any limitation it has Does this type of design can be used, This is small thing is confusing me about ip. Thanx in advance Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62733&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
I think something is being lost in the translation... This confuses me, too. --T Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62753&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Simple Ip issue (need help) [7:62728]
If you're asking what I think you're asking, then I think your answer is yes, but you won't be able to pass any traffic across the circuit. Unless you've confused me (it doesn't seem I would be the only one), then the answer might not be the same. - Original Message - From: "Monu Sekhon" To: Sent: Monday, February 10, 2003 12:13 AM Subject: Simple Ip issue (need help) [7:62728] > Hi All, > I have very simple question, Can we use duplicate ips on serial interfaces > among them seleves although we cannot use duplicate ip on serial with > Ethernet(lan interface) or loopback interface. > > > My topology is like this > > Client router server router(connected back to back) > 2 interfaces 2 inetrfaces > > > these routers connected back to back > > > configuration > int serial 0/0 > encap hdlc > ip address 1.1.1.1 255.255.255.0 > > int serial 0/1 > ip address 1.1.1.1 255.255.255.0 > encap hdlc > > > > now if all the two interfaces of serial even if given duplicate ip among > themselves works fine. no error from cli .interfaces are up > and i am able to ping remote side. > > > > The ques is that > > 1) Lan interface also was in different subnet but serial interface > doesnot accept that ips as duplicate or of loopback > > 2)What Implication such have on my design ,any limitation it has > > Does this type of design can be used, > > This is small thing is confusing me about ip. > > Thanx in advance Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62759&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
Only problem is which side are you pinging -Original Message- From: John Murphy [mailto:[EMAIL PROTECTED]] Sent: Monday, February 10, 2003 11:15 AM To: [EMAIL PROTECTED] Subject: Re: Simple Ip issue (need help) [7:62728] If you're asking what I think you're asking, then I think your answer is yes, but you won't be able to pass any traffic across the circuit. Unless you've confused me (it doesn't seem I would be the only one), then the answer might not be the same. - Original Message - From: "Monu Sekhon" To: Sent: Monday, February 10, 2003 12:13 AM Subject: Simple Ip issue (need help) [7:62728] > Hi All, > I have very simple question, Can we use duplicate ips on serial interfaces > among them seleves although we cannot use duplicate ip on serial with > Ethernet(lan interface) or loopback interface. > > > My topology is like this > > Client router server router(connected back to back) > 2 interfaces 2 inetrfaces > > > these routers connected back to back > > > configuration > int serial 0/0 > encap hdlc > ip address 1.1.1.1 255.255.255.0 > > int serial 0/1 > ip address 1.1.1.1 255.255.255.0 > encap hdlc > > > > now if all the two interfaces of serial even if given duplicate ip among > themselves works fine. no error from cli .interfaces are up > and i am able to ping remote side. > > > > The ques is that > > 1) Lan interface also was in different subnet but serial interface > doesnot accept that ips as duplicate or of loopback > > 2)What Implication such have on my design ,any limitation it has > > Does this type of design can be used, > > This is small thing is confusing me about ip. > > Thanx in advance Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62760&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
Hi All, Thanx again for all for contribution confusion still there , I am pinging remote side and I am able too. any comments from all(still confused with answers) Walker, James - Is wrote: > > Only problem is which side are you pinging > > > > > -Original Message- > From: John Murphy [mailto:[EMAIL PROTECTED]] > Sent: Monday, February 10, 2003 11:15 AM > To: [EMAIL PROTECTED] > Subject: Re: Simple Ip issue (need help) [7:62728] > > > If you're asking what I think you're asking, then I think your > answer is > yes, but you won't be able to pass any traffic across the > circuit. Unless > you've confused me (it doesn't seem I would be the only one), > then the > answer might not be the same. > > > - Original Message - > From: "Monu Sekhon" > To: > Sent: Monday, February 10, 2003 12:13 AM > Subject: Simple Ip issue (need help) [7:62728] > > > > Hi All, > > I have very simple question, Can we use duplicate ips on > serial interfaces > > among them seleves although we cannot use duplicate ip on > serial with > > Ethernet(lan interface) or loopback interface. > > > > > > My topology is like this > > > > Client router server router(connected back to back) > > 2 interfaces 2 inetrfaces > > > > > > these routers connected back to back > > > > > > configuration > > int serial 0/0 > > encap hdlc > > ip address 1.1.1.1 255.255.255.0 > > > > int serial 0/1 > > ip address 1.1.1.1 255.255.255.0 > > encap hdlc > > > > > > > > now if all the two interfaces of serial even if given > duplicate ip among > > themselves works fine. no error from cli .interfaces are up > > and i am able to ping remote side. > > > > > > > > The ques is that > > > > 1) Lan interface also was in different subnet but serial > interface > > doesnot accept that ips as duplicate or of loopback > > > > 2)What Implication such have on my design ,any limitation it > has > > > > Does this type of design can be used, > > > > This is small thing is confusing me about ip. > > > > Thanx in advance > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62762&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
If you ping you are probably pinging the Local IP.Try debug ip icmp to verify what you are pinging. Daniel Ladrach CCNP, CCNA WorldCom -Original Message- From: Monu Sekhon [mailto:[EMAIL PROTECTED]] Sent: Monday, February 10, 2003 12:03 PM To: [EMAIL PROTECTED] Subject: RE: Simple Ip issue (need help) [7:62728] Hi All, Thanx again for all for contribution confusion still there , I am pinging remote side and I am able too. any comments from all(still confused with answers) Walker, James - Is wrote: > > Only problem is which side are you pinging > > > > > -Original Message- > From: John Murphy [mailto:[EMAIL PROTECTED]] > Sent: Monday, February 10, 2003 11:15 AM > To: [EMAIL PROTECTED] > Subject: Re: Simple Ip issue (need help) [7:62728] > > > If you're asking what I think you're asking, then I think your > answer is > yes, but you won't be able to pass any traffic across the > circuit. Unless > you've confused me (it doesn't seem I would be the only one), > then the > answer might not be the same. > > > - Original Message - > From: "Monu Sekhon" > To: > Sent: Monday, February 10, 2003 12:13 AM > Subject: Simple Ip issue (need help) [7:62728] > > > > Hi All, > > I have very simple question, Can we use duplicate ips on > serial interfaces > > among them seleves although we cannot use duplicate ip on > serial with > > Ethernet(lan interface) or loopback interface. > > > > > > My topology is like this > > > > Client router server router(connected back to back) > > 2 interfaces 2 inetrfaces > > > > > > these routers connected back to back > > > > > > configuration > > int serial 0/0 > > encap hdlc > > ip address 1.1.1.1 255.255.255.0 > > > > int serial 0/1 > > ip address 1.1.1.1 255.255.255.0 > > encap hdlc > > > > > > > > now if all the two interfaces of serial even if given > duplicate ip among > > themselves works fine. no error from cli .interfaces are up > > and i am able to ping remote side. > > > > > > > > The ques is that > > > > 1) Lan interface also was in different subnet but serial > interface > > doesnot accept that ips as duplicate or of loopback > > > > 2)What Implication such have on my design ,any limitation it > has > > > > Does this type of design can be used, > > > > This is small thing is confusing me about ip. > > > > Thanx in advance Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62765&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
You can't have duplicate IP addresses anywhere. They have to be unique. The only exceptions would be if you were doing some sort of NAT or tunneling or something and the duplicates were hidden from each other. You don't get an error when you try to configure it because it's a lot harder for IOS to detect this on a serial interface than on an Ethernet interface. On Ethernet, a Cisco router ARPs for the address you give it. If it receives a reply, then it gives you an error and won't let you use the address. There's no ARP in serial land. You think you're pinging successfully, but how do you know who is really replying? Even if you could assign duplicate IP addresses, you shouldn't. You would wreak havoc with all sorts of things. There's no reason to do it either. If you're concerned with running out of addresses, just use private address. The 10.0.0.0 network has 16 million possibilities. Someone had to get blunt here! :-) ___ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com Ladrach, Daniel E. wrote: > > If you ping you are probably pinging the Local IP.Try debug ip > icmp to > verify what you are pinging. > > Daniel Ladrach > CCNP, CCNA > WorldCom > > > > -Original Message- > From: Monu Sekhon [mailto:[EMAIL PROTECTED]] > Sent: Monday, February 10, 2003 12:03 PM > To: [EMAIL PROTECTED] > Subject: RE: Simple Ip issue (need help) [7:62728] > > > Hi All, > Thanx again for all for contribution > confusion still there , > I am pinging remote side and I am able too. > any comments from all(still confused with answers) > > Walker, James - Is wrote: > > > > Only problem is which side are you pinging > > > > > > > > > > -----Original Message----- > > From: John Murphy [mailto:[EMAIL PROTECTED]] > > Sent: Monday, February 10, 2003 11:15 AM > > To: [EMAIL PROTECTED] > > Subject: Re: Simple Ip issue (need help) [7:62728] > > > > > > If you're asking what I think you're asking, then I think your > > answer is > > yes, but you won't be able to pass any traffic across the > > circuit. Unless > > you've confused me (it doesn't seem I would be the only one), > > then the > > answer might not be the same. > > > > > > - Original Message - > > From: "Monu Sekhon" > > To: > > Sent: Monday, February 10, 2003 12:13 AM > > Subject: Simple Ip issue (need help) [7:62728] > > > > > > > Hi All, > > > I have very simple question, Can we use duplicate ips on > > serial interfaces > > > among them seleves although we cannot use duplicate ip on > > serial with > > > Ethernet(lan interface) or loopback interface. > > > > > > > > > My topology is like this > > > > > > Client router server router(connected back to back) > > > 2 interfaces 2 inetrfaces > > > > > > > > > these routers connected back to back > > > > > > > > > configuration > > > int serial 0/0 > > > encap hdlc > > > ip address 1.1.1.1 255.255.255.0 > > > > > > int serial 0/1 > > > ip address 1.1.1.1 255.255.255.0 > > > encap hdlc > > > > > > > > > > > > now if all the two interfaces of serial even if given > > duplicate ip among > > > themselves works fine. no error from cli .interfaces are up > > > and i am able to ping remote side. > > > > > > > > > > > > The ques is that > > > > > > 1) Lan interface also was in different subnet but serial > > interface > > > doesnot accept that ips as duplicate or of loopback > > > > > > 2)What Implication such have on my design ,any limitation it > > has > > > > > > Does this type of design can be used, > > > > > > This is small thing is confusing me about ip. > > > > > > Thanx in advance > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62767&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
At 06:18 PM 2/10/2003 +, Priscilla Oppenheimer wrote: >You can't have duplicate IP addresses anywhere. They have to be unique. The >only exceptions would be if you were doing some sort of NAT or tunneling or >something and the duplicates were hidden from each other. > >You don't get an error when you try to configure it because it's a lot >harder for IOS to detect this on a serial interface than on an Ethernet >interface. On Ethernet, a Cisco router ARPs for the address you give it. If >it receives a reply, then it gives you an error and won't let you use the >address. There's no ARP in serial land. > >You think you're pinging successfully, but how do you know who is really >replying? > >Even if you could assign duplicate IP addresses, you shouldn't. You would >wreak havoc with all sorts of things. There's no reason to do it either. If >you're concerned with running out of addresses, just use private address. >The 10.0.0.0 network has 16 million possibilities. For what it's worth, duplicating the same IP across a set of DNS servers in the same AS can provide an interesting spin on resiliency. So long as you configure unique IP's for normal communication. This sort of thing works good for protocols that are stateless (UDP DNS) Anycast-RP in PIM networks also uses the same IP on multiple boxes :-) >Someone had to get blunt here! :-) Someone had to split some hair ! >___ > >Priscilla Oppenheimer >www.troubleshootingnetworks.com >www.priscilla.com > > > > >Ladrach, Daniel E. wrote: > > > > If you ping you are probably pinging the Local IP.Try debug ip > > icmp to > > verify what you are pinging. > > > > Daniel Ladrach > > CCNP, CCNA > > WorldCom > > > > > > > > -Original Message- > > From: Monu Sekhon [mailto:[EMAIL PROTECTED]] > > Sent: Monday, February 10, 2003 12:03 PM > > To: [EMAIL PROTECTED] > > Subject: RE: Simple Ip issue (need help) [7:62728] > > > > > > Hi All, > > Thanx again for all for contribution > > confusion still there , > > I am pinging remote side and I am able too. > > any comments from all(still confused with answers) > > > > Walker, James - Is wrote: > > > > > > Only problem is which side are you pinging > > > > > > > > > > > > > > > -Original Message- > > > From: John Murphy [mailto:[EMAIL PROTECTED]] > > > Sent: Monday, February 10, 2003 11:15 AM > > > To: [EMAIL PROTECTED] > > > Subject: Re: Simple Ip issue (need help) [7:62728] > > > > > > > > > If you're asking what I think you're asking, then I think your > > > answer is > > > yes, but you won't be able to pass any traffic across the > > > circuit. Unless > > > you've confused me (it doesn't seem I would be the only one), > > > then the > > > answer might not be the same. > > > > > > > > > - Original Message - > > > From: "Monu Sekhon" > > > To: > > > Sent: Monday, February 10, 2003 12:13 AM > > > Subject: Simple Ip issue (need help) [7:62728] > > > > > > > > > > Hi All, > > > > I have very simple question, Can we use duplicate ips on > > > serial interfaces > > > > among them seleves although we cannot use duplicate ip on > > > serial with > > > > Ethernet(lan interface) or loopback interface. > > > > > > > > > > > > My topology is like this > > > > > > > > Client router server router(connected back to back) > > > > 2 interfaces 2 inetrfaces > > > > > > > > > > > > these routers connected back to back > > > > > > > > > > > > configuration > > > > int serial 0/0 > > > > encap hdlc > > > > ip address 1.1.1.1 255.255.255.0 > > > > > > > > int serial 0/1 > > > > ip address 1.1.1.1 255.255.255.0 > > > > encap hdlc > > > > > > > > > > > > > > > > now if all the two interfaces of serial even if given > > > duplicate ip among > > > > themselves works fine. no error from cli .interfaces are up > > > > and i am able to ping remote side. > > > > > > > > > > > > > > > > The ques is that > > > > > > > > 1) Lan interface also was in different subnet but serial > > > interface > > > > doesnot accept that ips as duplicate or of loopback > > > > > > > > 2)What Implication such have on my design ,any limitation it > > > has > > > > > > > > Does this type of design can be used, > > > > > > > > This is small thing is confusing me about ip. > > > > > > > > Thanx in advance Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62780&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Simple Ip issue (need help) [7:62728]
No problem with the splitting of hairs. :-) I have been wondering why Cisco lets you do what the original poster is doing, which most of us misunderstood. He is using the same IP address on 2 serial interfaces on the SAME router. If you try to use the same IP address on two Ethernet interfaces, you just get an error when you try to configure the second Ethernet interface. With two serial interfaces, you don't get an error. Is this just an oversight? There are many such oversights in Cisco IOS. :-) Or maybe there is a real reason to do it. I said in my original message that there's no ARP on serial interfaces so the router can't easily figure out if anyone else is using its address like it does on Ethernet. On Ethernet the router can send an ARP to see if someone else replies. But that's someone else on the LAN connected to the interface, not another interface on the same router. So, if it gives you an error on Ethernet when you use an address you have already used on another Ethernet interface, why doesn't it give you an error for serial interfaces? Maybe there's an actual technical reason, although probably it's just an oversight. By the way, it lets you configure an Ethernet interface to use an address already in use on a serial interface, but if you try to do it in the other order then you get an error. That's probably just another oversight. Cisco has always given you enough rope to hang yourself. Decent error messages have never been any more important than ease-of-use. :-) Priscilla Peter van Oene wrote: > > At 06:18 PM 2/10/2003 +, Priscilla Oppenheimer wrote: > >You can't have duplicate IP addresses anywhere. They have to > be unique. The > >only exceptions would be if you were doing some sort of NAT or > tunneling or > >something and the duplicates were hidden from each other. > > > >You don't get an error when you try to configure it because > it's a lot > >harder for IOS to detect this on a serial interface than on an > Ethernet > >interface. On Ethernet, a Cisco router ARPs for the address > you give it. If > >it receives a reply, then it gives you an error and won't let > you use the > >address. There's no ARP in serial land. > > > >You think you're pinging successfully, but how do you know who > is really > >replying? > > > >Even if you could assign duplicate IP addresses, you > shouldn't. You would > >wreak havoc with all sorts of things. There's no reason to do > it either. If > >you're concerned with running out of addresses, just use > private address. > >The 10.0.0.0 network has 16 million possibilities. > > For what it's worth, duplicating the same IP across a set of > DNS servers in > the same AS can provide an interesting spin on resiliency. So > long as you > configure unique IP's for normal communication. This sort of > thing works > good for protocols that are stateless (UDP DNS) > > Anycast-RP in PIM networks also uses the same IP on multiple > boxes :-) > > >Someone had to get blunt here! :-) > > Someone had to split some hair ! > > > > >___ > > > >Priscilla Oppenheimer > >www.troubleshootingnetworks.com > >www.priscilla.com > > > > > > > > > >Ladrach, Daniel E. wrote: > > > > > > If you ping you are probably pinging the Local IP.Try debug > ip > > > icmp to > > > verify what you are pinging. > > > > > > Daniel Ladrach > > > CCNP, CCNA > > > WorldCom > > > > > > > > > > > > -Original Message- > > > From: Monu Sekhon [mailto:[EMAIL PROTECTED]] > > > Sent: Monday, February 10, 2003 12:03 PM > > > To: [EMAIL PROTECTED] > > > Subject: RE: Simple Ip issue (need help) [7:62728] > > > > > > > > > Hi All, > > > Thanx again for all for contribution > > > confusion still there , > > > I am pinging remote side and I am able too. > > > any comments from all(still confused with answers) > > > > > > Walker, James - Is wrote: > > > > > > > > Only problem is which side are you pinging > > > > > > > > > > > > > > > > > > > > -Original Message- > > > > From: John Murphy [mailto:[EMAIL PROTECTED]] > > > > Sent: Monday, February 10, 2003 11:15 AM > > > > To: [EMAIL PROTECTED] > > > > Subject: Re: Simple Ip issue (need help) [7:62728] > > > > > > > > > > > > If you're asking wh
RE: Simple Ip issue (need help) [7:62728]
At 01:20 AM 2/11/2003 +, Priscilla Oppenheimer wrote: >No problem with the splitting of hairs. :-) > >I have been wondering why Cisco lets you do what the original poster is >doing, which most of us misunderstood. He is using the same IP address on 2 >serial interfaces on the SAME router. Sonet APS comes to mind? I usually use a /29 with 4 addresses, but you could use the same address. >If you try to use the same IP address on two Ethernet interfaces, you just >get an error when you try to configure the second Ethernet interface. I can't think of a practical use for this myself. >With two serial interfaces, you don't get an error. Is this just an >oversight? There are many such oversights in Cisco IOS. :-) Or maybe there >is a real reason to do it. The more I think about it (over the last two paragraphs of your msg) the more APS seems the likely candidate. If you couldn't, this would be restrictive in some cases. Of course I'm thinking APS capable interfaces. >I said in my original message that there's no ARP on serial interfaces so >the router can't easily figure out if anyone else is using its address like >it does on Ethernet. On Ethernet the router can send an ARP to see if >someone else replies. But that's someone else on the LAN connected to the >interface, not another interface on the same router. > >So, if it gives you an error on Ethernet when you use an address you have >already used on another Ethernet interface, why doesn't it give you an error >for serial interfaces? Maybe there's an actual technical reason, although >probably it's just an oversight. > >By the way, it lets you configure an Ethernet interface to use an address >already in use on a serial interface, but if you try to do it in the other >order then you get an error. That's probably just another oversight. Would agree here. Might be something to do with internal mechanisms to map macs to IPs. Ie, if an interface is added, check the mac/ip binding list for duplicates and error if there is one. Such a mechanism wouldn't be relevant in SONET and for the APS reasoning, it may be expected that some interfaces share the same address. >Cisco has always given you enough rope to hang yourself. Decent error >messages have never been any more important than ease-of-use. :-) > >Priscilla > >Peter van Oene wrote: > > > > At 06:18 PM 2/10/2003 +, Priscilla Oppenheimer wrote: > > >You can't have duplicate IP addresses anywhere. They have to > > be unique. The > > >only exceptions would be if you were doing some sort of NAT or > > tunneling or > > >something and the duplicates were hidden from each other. > > > > > >You don't get an error when you try to configure it because > > it's a lot > > >harder for IOS to detect this on a serial interface than on an > > Ethernet > > >interface. On Ethernet, a Cisco router ARPs for the address > > you give it. If > > >it receives a reply, then it gives you an error and won't let > > you use the > > >address. There's no ARP in serial land. > > > > > >You think you're pinging successfully, but how do you know who > > is really > > >replying? > > > > > >Even if you could assign duplicate IP addresses, you > > shouldn't. You would > > >wreak havoc with all sorts of things. There's no reason to do > > it either. If > > >you're concerned with running out of addresses, just use > > private address. > > >The 10.0.0.0 network has 16 million possibilities. > > > > For what it's worth, duplicating the same IP across a set of > > DNS servers in > > the same AS can provide an interesting spin on resiliency. So > > long as you > > configure unique IP's for normal communication. This sort of > > thing works > > good for protocols that are stateless (UDP DNS) > > > > Anycast-RP in PIM networks also uses the same IP on multiple > > boxes :-) > > > > >Someone had to get blunt here! :-) > > > > Someone had to split some hair ! > > > > > > > > >___ > > > > > >Priscilla Oppenheimer > > >www.troubleshootingnetworks.com > > >www.priscilla.com > > > > > > > > > > > > > > >Ladrach, Daniel E. wrote: > > > > > > > > If you ping you are probably pinging the Local IP.Try debug > > ip > > > > icmp to > > > > verify what you are pinging. > > > > > > > > Daniel Ladrach > > >
RE: Simple Ip issue (need help) [7:62728]
rs in > > > the same AS can provide an interesting spin on resiliency. > So > > > long as you > > > configure unique IP's for normal communication. This sort > of > > > thing works > > > good for protocols that are stateless (UDP DNS) > > > > > > Anycast-RP in PIM networks also uses the same IP on multiple > > > boxes :-) > > > > > > >Someone had to get blunt here! :-) > > > > > > Someone had to split some hair ! > > > > > > > > > > > > >___ > > > > > > > >Priscilla Oppenheimer > > > >www.troubleshootingnetworks.com > > > >www.priscilla.com > > > > > > > > > > > > > > > > > > > >Ladrach, Daniel E. wrote: > > > > > > > > > > If you ping you are probably pinging the Local IP.Try > debug > > > ip > > > > > icmp to > > > > > verify what you are pinging. > > > > > > > > > > Daniel Ladrach > > > > > CCNP, CCNA > > > > > WorldCom > > > > > > > > > > > > > > > > > > > > -Original Message- > > > > > From: Monu Sekhon [mailto:[EMAIL PROTECTED]] > > > > > Sent: Monday, February 10, 2003 12:03 PM > > > > > To: [EMAIL PROTECTED] > > > > > Subject: RE: Simple Ip issue (need help) [7:62728] > > > > > > > > > > > > > > > Hi All, > > > > > Thanx again for all for contribution > > > > > confusion still there , > > > > > I am pinging remote side and I am able too. > > > > > any comments from all(still confused with answers) > > > > > > > > > > Walker, James - Is wrote: > > > > > > > > > > > > Only problem is which side are you pinging > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -Original Message- > > > > > > From: John Murphy [mailto:[EMAIL PROTECTED]] > > > > > > Sent: Monday, February 10, 2003 11:15 AM > > > > > > To: [EMAIL PROTECTED] > > > > > > Subject: Re: Simple Ip issue (need help) [7:62728] > > > > > > > > > > > > > > > > > > If you're asking what I think you're asking, then I > think > > > your > > > > > > answer is > > > > > > yes, but you won't be able to pass any traffic across > the > > > > > > circuit. Unless > > > > > > you've confused me (it doesn't seem I would be the > only > > > one), > > > > > > then the > > > > > > answer might not be the same. > > > > > > > > > > > > > > > > > > - Original Message - > > > > > > From: "Monu Sekhon" > > > > > > To: > > > > > > Sent: Monday, February 10, 2003 12:13 AM > > > > > > Subject: Simple Ip issue (need help) [7:62728] > > > > > > > > > > > > > > > > > > > Hi All, > > > > > > > I have very simple question, Can we use duplicate > ips on > > > > > > serial interfaces > > > > > > > among them seleves although we cannot use duplicate > ip > > > on > > > > > > serial with > > > > > > > Ethernet(lan interface) or loopback interface. > > > > > > > > > > > > > > > > > > > > > My topology is like this > > > > > > > > > > > > > > Client router server router(connected back to back) > > > > > > > 2 interfaces 2 inetrfaces > > > > > > > > > > > > > > > > > > > > > these routers connected back to back > > > > > > > > > > > > > > > > > > > > > configuration > > > > > > > int serial 0/0 > > > > > > > encap hdlc > > > > > > > ip address 1.1.1.1 255.255.255.0 > > > > > > > > > > > > > > int serial 0/1 > > > > > > > ip address 1.1.1.1 255.255.255.0 > > > > > > > encap hdlc > > > > > > > > > > > > > > > > > > > > > > > > > > > > now if all the two interfaces of serial even if > given > > > > > > duplicate ip among > > > > > > > themselves works fine. no error from cli .interfaces > > > are up > > > > > > > and i am able to ping remote side. > > > > > > > > > > > > > > > > > > > > > > > > > > > > The ques is that > > > > > > > > > > > > > > 1) Lan interface also was in different subnet but > serial > > > > > > interface > > > > > > > doesnot accept that ips as duplicate or of loopback > > > > > > > > > > > > > > 2)What Implication such have on my design ,any > > > limitation it > > > > > > has > > > > > > > > > > > > > > Does this type of design can be used, > > > > > > > > > > > > > > This is small thing is confusing me about ip. > > > > > > > > > > > > > > Thanx in advance > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=62815&t=62728 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
