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Unknown ISDN Dialer on Cisco 2620


i have one cisco 2620 router with a 4 Port ISDN WIC. This Router is a backup router. There are two main routers. All three are running hsrp. The isdn Router is the standby router in the hsrp group. The problem is that the 2620 is dialing sometime to his neighbor using the isdn lines. I have tried to find the problem running the debugger on the router. but i don´t know which process on the router like cdp or so is dialing to the isdn neighbor. Does anyone know how i can solve the problem and find the thing what is causing the dial?!

Thanks a lot.



Re: Unknown ISDN Dialer on Cisco 2620

If you do a 'show dialer' it will show you what the interesting traffic was that triggered the call. Call has to be active though.

Alternatively, you can probably do a 'debug dialer' and log it to the log. debug dialer shouldn't cause much output if your ISDN isn't up and down alot. This way you can catch the interesting traffic if you didn't get a 'show dialer' when it was up to find out.

You could also configure your dialer-list to reference an ACL and throw a 'log' keyword on the end to log access-list matches to log.

HTH, Erick

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Re: Unknown ISDN Dialer on Cisco 2620

Hi ,

thanks a lot for your quick answer. i have done a debug dialer and it shows me that the router itself triggers the call. As i know access-lists don´t work for the traffic which are generated by the router, ACL´s work only for traffic which is going through the router.So i know the router is initaiong the call. Is there another possibilitiy to get information why or which process is causing the call and how to stop this.



Re: Unknown ISDN Dialer on Cisco 2620

The dialer-list works differently then an access-group command so the log option would work fine.

When you did the debug, what was the output you saw? Can you post your config (sanitize it as needed) ?



Re: Unknown ISDN Dialer on Cisco 2620


The response given by ebergquist is dead on. You need to add log at the end of the permit statement in referenced in your access-list that your dialer list references dialer-list.

access-list 100 deny ip any host

access-list 100 deny ip any host

access-list 100 permit ip any any log

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