[j-nsp] BGP session going down on "invalid attribute list"

[Paul Goyette]

> Yesterday we had a BGP session fall away under our feet, and we don't
> completely understand why. We have a Juniper M7i running JUNOS 7.4.
> 
> Logging shows:
> Jan  3 16:37:18 juniper rpd[2727]: bgp_read_v4_update: NOTIFICATION
sent to *.21 (External AS X): code 3 (Update Message Error) subcode 1
(invalid attribute list)
> Jan  3 16:37:18 juniper rpd[2727]: bgp_event: peer .21 (External AS X)
old state Established event RecvUpdate new state Idle
> Jan  3 16:37:26 juniper rpd[2727]: bgp_pp_recv: rejecting connection
from .21 (External AS X), peer in state Idle

Turn on some additional BGP traceoptions to get the actual
packet contents/decode. 

Your router _received_ an UPDATE that it did not like, and
therefore is resetting the session.  The NOTIFICATION that
you are sending will contain at least part of the path 
attributes which it did not like.  If you turn on packet 
decoding, it will show you those attributes. 

The private-AS is not likely to be an issue...