traffic from Serial to second FA interface

[Andrew Schulz]

I have a little snag in my network configuration I need some help with.

I have a test PC on VLAN2 at a branch site. When I am on the router at the branch site I can ping the computer at 10.0.125.9. When I go back one hop to the router at HQ I cannot ping 10.0.125.9. My gut hunch is that it somehow involves the fact that we use an unnumbered interface for the serial link and so the serial link gets the same ip address as the data lan 10.0.25.101. We added a route to the HQ router so that 10.0.125.0 routes to 10.0.25.101 but that doesn’t help (see snippet from HQ router below)

       10.0.126.0/24 is directly connected, Serial4/0/18:0

       10.0.125.0/24 [1/0] via 10.0.25.101

       10.0.114.0/24 is directly connected, Serial4/0/5:0

A traceroute from HQ to the branch dies at 10.0.25.101

HQ#traceroute 10.0.125.9

Type escape sequence to abort.

Tracing the route to 10.0.125.9

  1 10.0.25.101 4 msec 12 msec 4 msec

  2  *  *  *

  3  *  *  *

Any suggestions?

[Richard Burts]

Andrew

It might be helpful if we had a better understanding of the topology of your network. What are the addresses on the interfaces of the HQ router and what are the interface addresses of the branch router?

But not knowing that information I will take a guess that the problem is that the PC does not have a correct default gateway configured. If the PC does have the correcct default gateway then my second guess is that the branch router does not have a correct route to the HQ router.

HTH

Rick

[Andrew Schulz]

Thanks for the reply Richard.

The HQ router has int fa0/0 as 10.0.0.1 - VLAN1, fa2/0 as 10.0.100.101 - VLAN2

The Branch router has int fa0/0 as 10.0.25.101 - VLAN1, fa0/1 as 10.0.125.101 VLAN2

From the HQ router I can ping the Branch router (Cisco 2801) and visa versa so I think the routes are correct there. From the Branch router I can ping the 10.0.125.9 test PC but can not ping it from the HQ router. I also confirmed the gateway was correct on the test pc.

The branch router has a single T1 to the Serial interface all traffic on the fa0/0 is routing correctly but not on the fa0/1. I think the key is the unnumbered interface for the serial link.

Note, we also enabled RIP which did not resolve the issue.

I do think it's a routing issue, but I'm not seeing where I'm missing it. I've attached the running-config with show IP Route. I hope this helps...

[Jigar Dave]

Hello Andrew,

from the config it seems that you have used interface fa0/0 as unnumbered and applied service policy but in actual fa0/1 is the interface where Voice VLAN is created.

try to give ip unnumbered fa0/1 on serial 0/1/0:0 instead of fa0/0.

******************************

Commands

conf t
int se0/1/0:0
no ip unnumbered fa0/0
exit
int se0/1/0:0
ip unnumbered fa0/1
no ip redirects
service-policy output VOICE
no sh
exit

******************************

hope to help

Jigar

[Andrew Schulz]

By doing that wouldn't we then loss connectivity to our Data side of the network?

[Andrew Schulz]

We got our VoIP network working however we are still not able to ping a PC on that VLAN 2 network from HQ.

We can however ping the VoIP controler at the remote site and any of the phones as well all from HQ.

Gateway on PC was correct, routing on the network looks correct and functions as so. It may be an issue with this one PC, but have not attempted using another test PC yet.