Cisco 1801 device repeatedly calling ISDN backup line

Unanswered Question
Jan 14th, 2009

Hi, we have a Cisco 1801 at one of our remote sites that uses an ADSL line for it's primary connection and ISDN as backup. Despite no apparent problems with the ADSL line the ISDN is repeatedly dialling the internet every 2-3 mins during office hours and considerable expense to the customer.

Does anyone know why this might be and how we can stop it from happening now and in the future?

Thanks, Rex

I have this problem too.
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Pravin Phadte Wed, 01/14/2009 - 04:00


You should have 2 interface config.

One for dailer and the other for ADSL.

Have you applied the command backup on the ADSL interface configured on the 1801 ?

"backup interface dailer 1" use ? for help i dont rem the complete command

Hope this helps

Richard Burts Wed, 01/14/2009 - 09:18


I am not sure that you need the backup interface command to fix this issue. From your description I would believe that there is some trafic going to the ISDN interface which is qualified as "interesting traffic" by the dialer group and dialer list. If you would post the config we might be able to help identify the issue more precisely.

Another suggestion would be to run debug dialer on the router. This should help identify the source of the traffic that is bringing up the ISDN. If you find that traffic and make it not interesting then you will have solved the problem.




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