BGP 4, auth error question.

Ben Black black at cypher.net
Fri Sep 18 21:35:44 UTC 1998


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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