Sometimes when configuring BGP you’ll come accross routes that show rib-failure. What exactly does this mean?
Have a look at this output:
R3#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
r> 172.16.220.0/24 172.16.220.1 0 0 3 i
*> 192.68.0.0/16 172.16.220.1 0 0 3 {2,1} i
*> 192.68.10.0 172.16.220.1 0 3 2 i
172.16.220.0/24 is showing up as r> – but what exactly is going on? There is a command you can use to see what’s happened: show ip bgp rib-failure
R3#sh ip bgp rib-failure Network Next Hop RIB-failure RIB-NH Matches 172.16.220.0/24 172.16.220.1 Higher admin distance n/a
Here it’s telling me that the BGP could not be injected into the routing table as there is already a route with a higher administrative distance there. This is proved with the ip routing table:
R3#sh ip route 172.16.220.0
Routing entry for 172.16.220.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/1
Route metric is 0, traffic share count is 1
Essentially a RIB-failure is a note letting you know that the route is in BGP, but it has not been injected into the IP routing table even though it is a valid and best route
(25 April 2012) – Note that rib failure prefixes are still advertised to BGP neighbours. This is not like EIGRP and RIP who will not. You can however prevent BGP from advertising rib-failure routes by configuring bgp suppress-inactive under the BGP process.
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