RE: Security of DNSBL spam block systems

["Phil Rosenthal" <pr () isprime com>]

IMHO Even the really large DNSBL's are barely used -- I think (much)
less than 5% of total human mail recipients are behind a mailserver that
uses one...
--Phil

-----Original Message-----
From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On Behalf Of
Big_Bandwidth
Sent: Tuesday, July 23, 2002 2:14 AM
To: nanog () nanog org
Subject: Security of DNSBL spam block systems



What are the security implications of someone hacking a DNSBL
(Real-time-spam-block-list) and changing the block list to include (deny
email from) some very large portion or all IPv4 space? 
 
Given that a signifigant number of the spam blocking lists seem to
operate on a shoestring budget in someone's basement, how can we be
assured that they have sufficient resources to secure their systems
adequatley, and monitor for intrusion 24x7?
 
Unless I am missing something, this would seem to be a real handy and
centralized method for someone to interfere substantially with the
proper operation of a few thousand email servers and hold up global
email traffic for a few hours.
 
-BB