[c-nsp] Cogent IOS upgrade == BGP-3, "update malformed"

[Gert Doering]

Hi,

On Sun, Aug 22, 2010 at 05:23:56PM -0600, randal k wrote:
> > http://www.ciscosystems.com/en/US/docs/ios/12_0s/feature/guide/s_befasp.html
> > no bgp enforce-first-as under your BGP config (or turning it on)
> > I seem to remember a bug related to that.  Not at the office or near a
> > router to check exactly which it was but had a similar problem albeit with
> > another provider.
> 
> No dice. Still died, same error, right at 70k routes. Thanks for the input
> though, I thought that first-as-hop *HAD* to match the remote AS; good to
> know that it doesn't!

On a normal customer-transit provider session, if it doesn't matches, it's
"something funny going on" - bug or malicious activity.

This is mainly used for peering point route-servers, where the route-server
will hand around AS paths from "peer X" to "peer Y" without introducing
the route server AS - so there, it will fail with "enforce-first-as"
(this is done to avoid making the AS path via the RS longer/different than 
via direct peering)

gert
-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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