BGP question

Thu Sep 17 06:55:16 UTC 2009

That routes detail command doesn't really give me that much extra info over
the other one.

Could it be that my import at RIPE for my customer AS is set to action
pref=100 instead of 120 is causing this?

Regards,

Rens
-----Original Message-----
From: Richard A Steenbergen [mailto:ras at e-gerbil.net] 
Sent: jeudi 17 septembre 2009 8:33
To: Rens
Cc: nanog at nanog.org
Subject: Re: BGP question

On Thu, Sep 17, 2009 at 06:49:37AM +0200, Rens wrote:
> *>i customer_range        Local IX                                     110
> 0          XXXX YYYY i
> *   customer_range         upstream provider                       100
> 0          AAAA BBBB  XXXX YYYY i
> *   customer_range         my customer                 0          120
> 0          YYYY YYYY i
> 
>        Last update to IP routing table: 0h23m34s, 1 path(s) installed:
>        Route is not advertised to any peers
> 
...
> But it seems to choose the set the one as local IX as best.
> 
> When I disable local IX it sets the one with my upstream provider as best.
> 
> Shouldn't it set the customer_range I receive from my customer as best
since
> it's highest local pref and advertise it to my upstream provider peer?

Yes, which means there must be something else wrong with that route to
keep it from getting installed as best path. That CLI output smells like
Foundry, and I don't remember exactly how it would show up, but on Cisco
for example "show ip bgp" not only shows your rib but also the adj rib
in for neighbors which have soft-reconfig enabled. This would show up as
(received) but not say "used", though again I'm not sure if Foundry does
this or how it would show up.

If you aren't doing something silly like outright rejecting the route in
the route-map or prefix-list on the neighbor, make sure the next-hop is
valid and reachable. IIRC Foundry doesn't do bgp next-hop recursion by
default, you have to manually enable it. If I remember my Foundry BGP
correctly (despite many years and a lot of therapy trying to repress
those memories) you can see more details with "show ip bgp routes detail
x.x.x.x".

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)