From: Nigel Taylor (nigel_taylor@xxxxxxxxxxx)
Date: Sun Nov 25 2001 - 22:09:58 GMT-3
Matt,
My first question here would be what interface were you peering
these BGP connections too.
In the case where R1 and R2 was making the BGP connection you could use any
interface providing there
was an IGP running. If no IGP was running then yes what you observed was
correct. In this case my next question to you would be "What's the first
1st requirement in the BGP path selection process"? As well with BGP being
a TCP(connection-oriented) connection between peers.. What does a 0/0 route
give you.
-Nigel
.
----- Original Message -----
From: "Matt Smith" <matt-n-donna@cablespeed.com>
To: <ccielab@groupstudy.com>
Sent: Sunday, November 25, 2001 8:02 PM
Subject: Interesting BGP problem
> Hey all,
> I just got done doing some last minute BGP practice scenarios in
preperation
> for my upcoming date with fate on 11/30. At any rate I was making some
quick
> and dirty lab scenarios to test some varios configurations and I found the
> following
>
> R1 <----->R2<------->R3
>
> R1 is configured with a 0.0.0.0 route to R2 and R3 with a 0.0.0.0 route to
R2
> as well. I pinged from R1 to R3 and communicationed worked fine.
>
> Now I issued router bgp 100 on both R1 and R2 and defined the neigh bor
> statements for iBGP.
>
> The BGP relationship never came up. AS#s were correct on both router
> processes and neighbor statements and the IP addresses were correct as
well.
>
> show ip bgp neighbor reports that neither router has sent or recieved and
BGP
> messages and a deb ip packet verifies that this is true.
>
> What was the culprit? well........... Make a guess then read on
>
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> I issued a static route for the specific address of the neighbor on each
> router (R1 and R3) pointing to R2 and the relationship came up.
Apparently
> BGP requires a route in the routing table for the nieghbor address and
will
> not use the 0.0.0.0 route. IP classless enabled on both routers and as I
> stated both routers could ping one another. Has anyone ever read and
> documentation supporting this to be true? I have never seen any rules
> pertaining to this issue so I thouht I would share it with the group.
Just a
> quick tidbit. Hope it helps someone someday.
>
> Luck to All
>
> Matt Smith
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