router bgp 65535 neighbor 1.1.1.1 remote-as 3356 neighbor 1.1.1.1 prefix-list infilter in neighbor 1.1.1.1 prefix-list outfilter out neighbor 1.1.1.1 route-map bump-local-pref in ! ip prefix-list bump-local-pref-routes seq 5 permit 100.10.20.30/24 ip prefix-list bump-local-pref-routes seq 10 permit 100.10.20.31/24 ! route-map bump-local-pref permit 10 match ip address prefix-list bump-local-pref-routes set local-preference 200 ! route-map bump-local-pref permit 20
So, the routes in question have their pref bumped to 200:
router#sh ip bgp 100.10.20.30 BGP routing table entry for 100.10.20.30/24, version 254855 Paths: (1 available, best #1, table Default-IP-Routing-Table) Advertised to non peer-group peers: 192.168.1.100 192.168.1.251 192.168.1.252 3356 3549 1.1.1.1 from 1.1.1.1 (1.1.1.1) Origin IGP, metric 0, localpref 200, valid, external, best
But the routes from our other transit provider -- which should be over an iBGP session with another of our routers -- have vanished. This is the case for any prefix which this router is first choice, not just the two routes in my prefix-list.
If I turn off the route-map and clear the session I get the prefixes from the other peer back:
router#sh ip bgp 100.10.20.30.0 BGP routing table entry for 100.10.20.30/24, version 289175 Paths: (2 available, best #2, table Default-IP-Routing-Table) Flag: 0x800 Advertised to non peer-group peers: 192.168.1.100 192.168.1.251 192.168.1.252 174 3549 192.168.1.100 from 192.168.1.100 (192.168.1.100) Origin IGP, metric 162100, localpref 100, valid, internal Community: 174:21000 174:22013 3356 3549 1.1.1.1 from 1.1.1.1 (1.1.1.1) Origin IGP, metric 0, localpref 100, valid, external, best
What gives? I'm not doing anything to the other routers in our network; just tweaking two prefixes coming from one particular peer. (It so happens that this router *does* choose the right route; I need to flood this to the other iBGP peers, hence local-pref tricks).
I thought this might be an IOS bug (there was one with similar problems to mine but I've forgotten its number) so I just upgraded to 12.3(21). Same problem.
Any ideas? This is on a 7204VXR, BTW.
Cheers,
Mark