[74701] in North American Network Operators' Group
Re: BCP38 making it work, solving problems
daemon@ATHENA.MIT.EDU (Niels Bakker)
Tue Oct 12 04:49:49 2004
Date: Tue, 12 Oct 2004 10:49:13 +0200
From: Niels Bakker <niels=nanog@bakker.net>
To: nanog@merit.edu
Mail-Followup-To: nanog@merit.edu
In-Reply-To: <Pine.GSO.4.58.0410120312380.531@sharpie.argfrp.us.uu.net>
Errors-To: owner-nanog-outgoing@merit.edu
* christopher.morrow@mci.com (Christopher L. Morrow) [Tue 12 Oct 2004, 05:18 CEST]:
> a common occurance we've seen is a customer of a customer NOT
> announcing , nor planning on announcing, their routes to their
> upstream#1 which they use ONLY for outbound traffic (cheap transit for
> instance, and perhaps only for some portions of their total sources)
> though they announce to upstreams#2-N the proper sources to gather the
> return traffic. These things make uRPF 'difficult'.
You could use uRPF-loose there, or the customer could do:
!
route-map outbound-only permit 10
match prefix-list myprefixes
set community no-export
!
And bash the people who, in this age, don't have "neighbor x.y.z.a
send-community" on all their BGP sessions.
-- Niels (who recently had a CCIE claim that he was "not aware
of a single ISP accepting communities from its peers"
- well, my experience begs to differ, with his
employer a rare and lonely exception to the rule)
