Is it time to abandon bogon prefix filters?

Darden, Patrick S. darden at
Wed Aug 6 08:18:57 CDT 2008

Yes.  1918 (10/8, 172.16/12, 192.168/16), D, E, reflective (outgoing
mirroring), and as always individual discretion.

--Patrick Darden

-----Original Message-----
From: Leo Bicknell [mailto:bicknell at]
Sent: Wednesday, August 06, 2008 9:10 AM
To: nanog at
Subject: Is it time to abandon bogon prefix filters?

"Bogon" filters made a lot of sense when most of the Internet was
bogons.  Back when 5% of the IP space was allocated blocking the
other 95% was an extremely useful endevour.  However, by the same
logic as we get to 80-90% used, blocking the 20-10% unused is
reaching diminishing returns; and at the same time the rate in which
new blocks are allocated continues to increase causing more and
more frequent updates.

Have bogon filters outlived their use?  Is it time to recommend people
go to a simpler bogon filter (e.g. no 1918, Class D, Class E) that
doesn't need to be updated as frequently?

       Leo Bicknell - bicknell at - CCIE 3440
        PGP keys at

More information about the NANOG mailing list