With all the recent talk about filtering, I figured now was a good time to update my list of evil /24 announcers... There are currently over 63k /24s out of 113k total unfiltered announcements (over 55%). http://www.e-gerbil.net/ras/projects/ipaddr/amuck-071902.txt This scan is done from the point of view of Williams (AS7911) transit, a fairly "average" unfiltered view of around 113k routes. It's not perfect, but it's pretty easy to go down the list and verify which ones are really poluting the internet. The reason these don't get picked up on other peoples "cidr scans" is that they have "gaps", so they are not perfectly cidr-able. The reasons for these announcements vary, including obvious incompetence and cable/dsl companies without a "backbone" connecting their various POPs announcing a /24 for each location to a single transit provider. If I had more free time I would extend this analysis past /24s, but since they're such a huge amount of polution it's a good place to start. If someone wanted to do an analysis of routes from a common block with identical attributes, I suspect they would find it a bigger cause of net polution than multihomers punching holes. For quick complaining, the top 10 offenders are: ASN Name Reg'd Netblock Prefixes --- ---- -------------- -------- 6595 DoD Dependents Schools - Europe 204.218.0.0/15 236 22927 TELEFONICA DE ARGENTINA 168.226.0.0/16 167 7029 Alltel Information Services 166.102.0.0/16 128 7303 Telecom Argentina Stet-France 200.43.0.0/16 127 14654 Wayport 64.134.0.0/16 113 16473 Bell South 198.146.0.0/16 111 11492 Cable One 24.116.0.0/16 108 18687 MPower Communications 208.57.0.0/16 98 7132 Southwestern Bell 207.193.0.0/16 89 1580 Army HQ, 5th Signal Command 144.170.0.0/16 88 -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras PGP Key ID: 0x138EA177 (67 29 D7 BC E8 18 3E DA B2 46 B3 D8 14 36 FE B6)