[quagga-users 14631] Re: Weird BGP Behavoiur

Hi

Welcome to a world of fun and pain.

On 05/03/2017 00:40, Richard J Palmer wrote:
> Hi
>
> I am seeing odd behavour on one of our quagga boxes here and I am
> looking for some help

> And some internal sessions:
>
> 9.8.7.6   4 12345     100     661        0    0 530342 01:36:41        3
> 5.6.3.2   4 12345   18551    1364        0    0 525874 01:36:43    95301
>
> You will see the 'OutQ' Colum is HUGE and does not decrease. I can't see
> any errors - IF I run sh ip bgp 8.8.8.8 for example it will show the
> route is being advertised to a peer router - BUT the remote router does
> not have the prefix prsumably as it i stuck in the queue.

This is similar to the "IPv6 routes not propagating via iBGP" problem 
that a number of us have randomly on some devices.  I have also seen 
this with some v4 prefixes, normally customers who are dual-homed and 
have flapped a bit between primary and backup; and you end up with the 
route 'stuck' on one or more routers.

We actually have a script that runs every few hours now to check that 
across the AS, every router has the same next-hop for these prefixes 
(they have set local-prefs so this should absolutely be the case) - as 
in the past the failure of the internal routes to update caused routing 
loops and general badness.

It is a royal pain to debug because it seems almost un-reproducible in 
the lab :(

FWIW, I have downgraded to 0.99.23.1 across the board as that is the 
last release of Quagga that I can find that definitely does not have 
this issue.

Paul.