Jeff, Are you a peer or customer of ATT? or are you seeing these from your upstream? If it is the first case, you can ask ATT to not leak more specific routes to you. Also, they have a community you can use to block them. If it is the second, please talk to your upstream. That means they are leaking ATT more specifics. I know of one provider that has done this more than once in the past... Contact them and make sure they have the correct route-maps/filters in place. And if you really dont like seeing them... prefix-list idontlikethis 12.0.0.0/8 le 8 that should solve your problem. On Thu, 9 Aug 2001, Jeff Harper wrote:

Just curious if anyone has noticed the leaking of the more specific routes of AT&T's IP space in their BGP table. Here's what we're seeing in ours:

#s ip ro 12.0.0.0 Routing entry for 12.0.0.0/8, 589 known subnets Variably subnetted with 9 masks

B 12.23.26.0/23 [20/0] via x.x.x.x B 12.28.18.0/24 [20/0] via x.x.x.x B 12.33.46.0/24 [20/0] via x.x.x.x, etc.....

I should just see the aggregation of the /8, but something changed on 8/7/2001 at precisely 8 AM Eastern time. The same is with their 24/8 and their other networks as well. I have about 40,000 superfluous networks in my BGP table. ;)

Jeff