nanog mailing list archives

Re: BGP 4, auth error question.


From: Ben Black <black () cypher net>
Date: Fri, 18 Sep 1998 17:35:44 -0400

On Fri, Sep 18, 1998 at 05:14:28PM -0400, Chris Morrell had most eloquently written:

The Cisco is probably running IOS 11.1(20)CC.  This version has a bug in
it that assumes the other side will understand its request to negotiate
MBGP (which there is no RFC for and which seems to be Cisco proprietary at
this point).


actually, i think the bug relates to Capabilities Negotiation, which is a
draft RFC at this point.  there is great irony in capabilities negotiation
causing a BGP session to reset because it was created specifically to
avoid connection resets from unknown Optional Parameters in an OPEN message.

The BGP session will come up with a Cisco which can't run MBGP, but it
doesn't seem to work for other routers. (notably routers using gated
derived code.

Changing the IOS will fix the problem, but the better short term thing to
do is to have the Cisco side add the following line to their BGP
configuration for your connection:

neighbor AA.BB.CC.DD dont-capability-negotiate


the real bug is not that cisco implemented capability negotiation incorrectly,
but that it is on by default long before anyone else has implemented it.

If you want more details and the actual Cisco Bug ID, I can find that for
you.

Chris



ben



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