Conditional ISIS default route advertisement

I'm toying around with conditional default advertisement in ISIS and I just
can't get it tuned right. A router, let's call it R2, has an eBGP peer and
another "internal" peer and it's learning a default from both. I'm trying
to configure R2 such that it only advertises a default if it is learning it
from its eBGP peer. The problem I'm having is that no matter how I've
configured it, whenever I add a route map to the default-information
originate command, it just stops advertising the default. I haven't found
any example configurations, so I really don't know how to craft the route
map. I've tried matching the next hop of the route and I've tried using an
ACL, but neither is working.

The eBGP peer is 3.3.3.3. This is the first route map I tried:

route-map ISIS_DEFAULT permit 10
 match ip next-hop 3.3.3.3

That didn't work at all. I was hoping it would match on the route in the
routing table, but it didn't seem to work at all. So, I tried this:

access-list 100 permit 0.0.0.0 0.0.0.0 3.3.3.3 0.0.0.0

route-map ISIS_DEFAULT
 match ip address 100

I thought that would look for a 0.0.0.0 route in the table with a next-hop
of 3.3.3.3, but that didn't work either. It's been a LONG time since I've
done anything like this. Please refresh my memory. :)

I'm sure I'm missing something obvious, but what is it?

Thanks,
John

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Received on Tue Jul 31 2012 - 20:09:42 ART