Rib-failure BGP

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>        0             0 3 i
*>        0             0 3 {2,1} i
*>                      0 3 2 i 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        Higher admin distance              n/a

Here it’s telling me that the BGP could not be injected into the routing table as the BGP route has a higher admin distance than an identical route in the table. This is proved with the ip routing table:

R3#sh ip route
Routing entry for
  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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