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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Strange BGP announcement.
On Auguest 6th Brett Frankenberge wrote: > > :: Victor L. Belov writes :: > > > > AS8263 encounted the same problem today. The problem is that cisco > > handle this incorrect update normally, but it couses Bay Networks > > routers to crash =() Seems to be another problem on the Internet. > > Bays don't crash (at least not in the general case ... for example, > mine stayed up this time and the last time this happened), but they do > send a NOTIFY and bring down the BGP session, as required by the RFC. > (I believe gated does this also.) > > The reason this issue causes problems is that Cisco violates the RFC > and passes the bad announcement around, so it eventually reaches most > non-Cisco routers who properly terminate the BGP connection. If Cisco > would do the NOTIFY upon receipt of the announcement, then the > information wouldn't spread, and only one router's worth of peerings > (i.e. the guy who "started" the bad annoucnement) would be lost. > > > Neil J. McRae wrote: > > > > > > Aug 6 13:46:20 BGP RECV 207.45.199.225+179 -> 207.45.199.226+1935 > > > Aug 6 13:46:20 BGP RECV message type 2 (Update) length 71 > > > Aug 6 13:46:20 BGP RECV flags 0x40 code Origin(1): Incomplete > > > Aug 6 13:46:20 BGP RECV flags 0x40 code ASPath(2): 6453 701 65525 ((65523)) 356 > > > 1 1691 > > > Aug 6 13:46:20 BGP RECV flags 0x40 code NextHop(3): 207.45.199.225 > > > Aug 6 13:46:20 BGP RECV 204.174.40/24, 204.239.26/24, 204.239.27/24, 204 > > > .239.147/24 > > > Aug 6 13:46:20 > > > Aug 6 13:46:20 bnp_path_attr_eer: peer 207.45.199.225 (External AS 6453) bad up > > > date send NOTIFY flag 0 type 0 err_subcode 11, data 0 > > > Aug 6 13:46:20 NOTIFICATION sent to 207.45.199.225 (External AS 6453): code 3 ( > > > Update Message Error) subcode 11 (AS path attribute problem) data > > > Aug 6 13:46:20 > > > Aug 6 13:46:20 BGP SEND 207.45.199.226+1935 -> 207.45.199.225+179 > > > Aug 6 13:46:20 BGP SEND message type 3 (Notification) length 21 > > > Aug 6 13:46:20 BGP SEND Notification code 3 (Update Message Error) subcode 11 ( > > > AS path attribute problem) > > > Aug 6 13:46:20 > Hmm. I'm seeing something similar tonight... seeing more than one of my upstreams send me junk, and my routers send back a notify and drop the session (and my reading of the RFC matches Brett's). Since this isn't directly my upstream's problem I've edited them out of the log (actually, this could have come from more than one of my upstreams) Nov 8 17:45:26 BGP RECV x.x.x.x+179 -> x.x.x.x+1161 Nov 8 17:45:26 BGP RECV message type 2 (Update) length 64 Nov 8 17:45:26 BGP RECV flags 0x40 code Origin(1): Incomplete Nov 8 17:45:26 BGP RECV flags 0x40 code ASPath(2): (0x02 0x07 0x0f 0x7f 0x02 0xbd 0x0d 0xa5 0x03 0x30 0x03 0x2f 0x03 0x2e) Nov 8 17:45:26 BGP RECV flags 0x40 code NextHop(3): x.x.x.x Nov 8 17:45:26 BGP RECV flags 0xc0 code Aggregator(7): 6218 206.53.128.254 Nov 8 17:45:26 BGP RECV 206.148.144/22 Nov 8 17:45:26 Nov 8 17:45:26 bnp_path_attr_eer: peer x.x.x.x (External AS yyyy) bad update send NOTIFY flag 0 type 0 err_subcode 11, data 0 Nov 8 17:45:26 NOTIFICATION sent to x.x.x.x (External AS yyyy): code 3 (Update Message Error) subcode 11 (AS path attribute problem) data Nov 8 17:45:26 Nov 8 17:45:26 BGP SEND x.x.x.x+1161 -> x.x.x.x+179 Nov 8 17:45:26 BGP SEND message type 3 (Notification) length 21 Nov 8 17:45:26 BGP SEND Notification code 3 (Update Message Error) subcode 11 (AS path attribute problem) Nov 8 17:45:26 (We saw the problem start around 1640 GMT tonight) Problem at AS6218 perhaps ? (of course if this is the result of some random corruption that can't be relied on... ) Anyone else see anything ? Regards, Andrew -- Andrew Bangs, Network Engineering Manager, Demon Internet Ltd [email protected] http://www.demon.net/ http://www.demon.nl/ Network Engineering: +44 (0)181 371 1204 [email protected]
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