When ISDN doesn't hang up execute the command 'show dialer' and that would show the source and destination IP that kept the link up. Based on that you should be able to fix the issue.

HTH

Sundar

Sidney

I believe that Sundar is on the right track in identifying what is keeping the ISDN up is that there is "interesting" traffic. The configuration posted includes the definition of "interesting" traffic:

dialer-list 1 protocol ip list 101

access-list 101 deny eigrp any any

access-list 101 deny ip any host 255.255.255.255

access-list 101 permit ip any any

So "interesting" traffic excludes eigrp and broadcast traffic and includes everything else. You need to identify what that other traffic is and to address that in access list 101.

HTH

Rick

shall do, but a quick question. If EIGRP is routing everything through the other router and the static that get stuck has an admin of 240, what would be routed across the link and why?

Sidney

Knowing some details about the static route would make it easier to answer your question. I can not tell from your description whether the static route with admin distance of 240 is a default route or is something different. The behavior you describe almost makes me think it might be something different.

In general static routes with high admin distance like this are floating static routes. The idea of the floating static route is that it is a static route configured with a higher then default admin distance. The default admin distance for static routes is 1 which makes them very believable. If you have a static route with default admin distance of 1 then it is better than any dynamic route for the same prefix. When you configure the static with a higher admin distance that allows the dynamic route to be used when it is available and allows the static route to be used when the dynamic route is not available. And when the dynamic route is available again it should go into the routing table and the static should float away.

Your description sounds like the floating static route is not getting out of the way when the EIGRP route comes back. If you can provide some details about the static route (and maybe a config of the router) it might help us to figure out what is happening.

HTH

Rick

Here is the amended router config. I hope this is enough info.

When EIGRP adverts stop from the telco router my ISDN dials, and I get the following. which shows the ISDN route in the routing table, but notice that when I do a traceroute everything is routing through the better metric on the MPLS router(as it should, but the static route doesn't drop and the ISDN stays connected until I clear the ip route 0.0.0.0. then EIGRP advertises the default route and ISDN hangs up.

[as already mentioned in another thread]

The problem with 'backup' command is thats it doesn't make the line go active when for example there is a 'black hole' in the network, or the FR PVC status is not reliable, or many other situations that dictates the use of floating static routes for a professional design.

Paolo

I am not sure what other thread you are referencing, but I agree that in recent practice the use of floating static routes for redundancy is more preferred than the backup command. I am also not sure of the logic when Vinay says that backup command removes the need for static routes. The backup command only controls the conditions in which the backup interface will become active and as far as I know has no change in the routing logic.

HTH

Rick

Well, in fact once "backup interface" successfully triggers up an interface that is configured for dynamic routing, here we have the situation Vinay was referring. No need for floating static routes.

Anyway as we were saying the "backup interface" is very limited. Here is another reason: you cannot dial into an interface configured as "backup". Thing that you want to do for testing or other purposes. With floating static, it is perfectly possible.