Cisco routers will not interject BGP learned routes into their routing
table if the next-hop is only known via a default.
To fix this you must either include a static to your next-hop, change it
to something the router does know (i.e. via a directly connected
interface), or include it in another router in your network via your
IGP.
David
-----Original Message-----
From: Elijah Kagan [mailto:elijah@netvision.net.il]
Sent: Sunday, June 17, 2001 1:24 AM
To: cisco-nsp@puck.nether.net
Subject: [nsp] A question regarding BGP next-hop reachability.
Suppose there is a router (a Cisco router, of course) that learns
nothing
but a default gateway from its IGP. It also has an iBGP session with its
default router and receives the full Internet routing table. The default
router acts as a route-reflector.
Now here is the problem. The next-hop of every BGP prefix it learns is
reachable via IGP's default gateway, but for some reason it is not good
enough, BGP marks it as inaccessible and disregards the prefix.
This situation could appear in L1 router that learns a prefix
originating
form a different IS-IS area.
Please advise....
-- elijah
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:42 EDT