Whilst labbing out a BGP scenario I came across the following in a sh ip bgp output.

I noticed in the output that I had a RIB-failure. Failure. I immediately started to wonder what exactly did this mean. I could still ping the hosts at the end of the route and the route was marked as best.

A little investigative work yielded these results

Firstly, a RIB-Failure isn’t a bad thing. It is a fetautre that was introduced in IOS 12.2T. It essentially means that a BGP route cannot be placed into the routing table. The reason being is that a route with a lower AD is in the routing table.

In the scenario I was working out, I had placed a static route for traffic to go to my ISP. This was on the network. Due to static routes having an AD of 1, this beat my eBGP route.

Previously, routes that now days would be marked with an r for RIB-Failure, would have silently slipped into the nether with no reason as to why they didn’t make the routing table. This feature at a glance allows Network Engineers/Admins to note a route has a better path injected into the routing table that isn’t by the BGP process.

The more you know. 🙂

2 thoughts on “RIB-Failure. Not as bad as I immediately thought

  1. Yes! It is a very handy command. I used it when doing a BGP and found it will state the reason why the route was not injected into the RIB.

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