BRI to PRI DDR authentication failure using CHAP

[asantosp]

Here is the scenario:

I have a branch office with an ISDN line as backup line and a PRI T1 line in the HQ office.

When the branch office's frame relay link goes down, the router automatically dials out to the HQ office using the ISDN line. After dialing out, the ppp authentication process starts, but the branch offcie router do not get a response from the HQ router when the CHAP request is sent.

Attached to the post is the configuration of both routers and a debug output of the branch office router when dialing out to the HQ router.

The configuration seems to be fine, but I cannot connect.

Any idea?

[Kevin Dorrell · Accepted solution]

On your HQ router, on the Dialer interface, you need dialer remote-name name, where name is the hostname of the remote router. In fact, looking at your config, you seem to have several usernames, I guess for several remote sites. You should create a dialer interface for each one, and distinguish them by the dialer remote-name command. When the call comes in, the HQ router uses the CHAP information to bind the call to one of the dialer interfaces. You also need to put the ISDN in a dialer pool and configure the dialer interface to use that pool.

OR

If you are only using the ISDN for this one site, you need to specify dialer remote-name on the S0/0:23.

Kevin Dorrell

Luxembourg

[asantosp]

Great Kevin.

I'll do the changes you sugested and I'll post back the results.

Antonio Ml. Santos

[asantosp]

Hi Kevin

Look, the problem was solved, the end configuration was not exactly the one I posted but the input you gave helped me to solve this issue. Now I'm able to dial to the PRI T1 without any problem.

If you wish to, I can post a new message with the final configuration.

Thanks for the adviced.

[Kevin Dorrell]

Glad to hear it's working now. With dialup there are always n**2+1 ways of doing things, so you have to choose the particular configuration that suits your particular connectivity requirements.

If you would like to post some of the final configuration just for the record, that might help someone who has the same problem in the future.

Hope to hear from you again on the forum.

Kevin Dorrell

Luxembourg

[asantosp]

Hi Kevin.

Here you go, I'm posting the configuration of both routers and a debug file contaning the results of the communication between both routers.

Thanks for your support.