WAN goes down, router interface stays up, need secondary default route

Unanswered Question
Aug 8th, 2008

Hello. We have a very important site that needs to be available 24/7, so along with our standard MPLS data circuit we installed a point to point dedicated line that we can use to connect to head office in case the main MPLS circuit fails. The thought was to add a secondary default route with a higher admin distance. The problem with this is that the normal default route points to the LAN side IP of the providers router, which is always available even when the WAN is not. This means that the secondary default route will not be injected into the routing table, and the site will remain down. Unplugging this interface would get it working, but we are looking for something automatic. There are no dynamic routing protocols in use between our 3750 (which acts as our clients default gateway) and the providers router. Only a static default route pointing to the providers router. I thought about PBR, and using the recursive next hop feature, but am unsure if that will work for me. I've attached a diagram, can someone give me some ideas?


I have this problem too.
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Richard Burts Fri, 08/08/2008 - 11:30


It is a fairly common issue when default routes point at a LAN interface and do not go down when outside connectivity is lost. PBR with recursive next hop is a creative solution. But there is a much better solution available. Cisco has introduced a feature called Reliable Static Routing Backup Using Object Tracking. It uses the capabilities of Object Tracking to determine that the primary static (default) route should be withdrawn because connectivity to outside has been lost. This link should give you information to implement this feature:




poulid Fri, 08/08/2008 - 14:30

Wow, I've never heard of that before. This seems like exactly like the thing I'm looking for, thanks a lot. Any idea if this is supported on the 3750, I'm running 12.2(35)SE5?

Thanks again.


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