CISCO Serial interface problem

[dd2775]

Hello,

I have cisco 2600 router with 2 Serial & 2 Fastethernet ports, we have two ISP's (XXX & YYY) XXX configured on Serial 0/1 and YYY Serial 0/0. The IP address of Serial 0/1 192.168.1.1 and the second Serial is unnumbered but take the address from Fastethernet 0/0. Every thing works fine, but the problem is that the serial 0/0 which is unnumbered stops working when the XXX ISP goes down/ or we shutdown the Serial 0/1 interface. AS soon as the serial 0/1 or XXX ISP comes up both the links start working.

Can anybody help me in this.

Rgds
Darshan

 

[anddaley]

Define down. Do you mean the ser 0/0 interface physically is down on does it just stop routing?

 

[dd2775]

It just stops routing

 

[themut]

issue the following command:

show interfaces

and post the results in order to determine the state of the interfaces.

 

[anddaley]

You need to make sure that you have a route for the other serial 0/0 interface. Also give it a greater AD (Administrative Distance) lets say 20.

What may be happening is that when your primary link goes down there no routes to send traffic through the other interface.

Also on the more complicated side we may have to get NATing involved. You may need to set up nat between your inside int and the secondary serial int. This maybe an issue as well as it may not...

Get the static route issue going for the other serial interface 0/0 and let me know.