On Fri, 9 Sep 2005, Richard A Steenbergen wrote:
On Fri, Sep 09, 2005 at 11:12:25AM -0400, Drew Linsalata wrote:
Apologies for a post of an operational nature, but is anyone else seeing problems with AT&Ts 12/8 block?
From a New York router connected to Global Crossing and Peer 1:
border-1.nycmny> sh ip bgp 12.xxx.xxx.xxx
BGP routing table entry for 12.0.0.0/8, version 86901457 Paths: (2 available, best #1) Not advertised to any peer 3549 12956 26210 64.213.176.97 from 64.213.176.97 (208.50.59.1) Origin incomplete, metric 2602, localpref 100, valid, external, best, ref 2 Community: 232589665 232618104 13768 12956 26210, (received-only) 64.34.84.117 from 64.34.84.117 (216.187.124.10) Origin incomplete, localpref 100, external, ref 2
Route views is showing a 12/8 with a fair amount of dampening/flap penalties in the last 10-12 minutes.
Looks like 12956 is announcing some /8s to every peer and transit
It looks like 12956 is propagating announcements from their customer 26210 of these /8 routes. It looks like 12956 does not have correct policies in place to block such announcements from their customers as many of the large ISPs in US do (mostly by requiring customers to pre-authorize and give list of blocks that they would be announcing) and that is why from time-time things like this leak out (which they deal with each time after the fact). It does seem appropriate that if 12956 is unable to put appropriate policies in place to make sure things like this do not happen, then all its announcements will have to be double-checked and pre-authorized by its transits i.e. GBLX and Sprint. --- William Leibzon Elan Networks william@elan.net