I guess its been long enough since the last time that folks have gotten lax with their filters. Filtering default, loopback, etc should be in every peer's BGP configuration whether you trust them or not. Who do you blame, the fool who announces default to the world, or the world for listening to it. Every router I know has enough memory and processing power to filter the basic (updated) martian list. This was a preventable accident. On Tue, 14 November 2000, Randy Bush wrote:
what am i misunderstanding here
route-views.oregon-ix.net>sh ip bg 48.0.0.0 BGP routing table entry for 0.0.0.0/0, version 27074 Paths: (1 available, best #1) Not advertised to any peer 3333 5597 193.0.0.56 from 193.0.0.56 (193.0.0.56) Origin IGP, localpref 100, valid, external, best