At 11:04 AM 2/20/00 -0800, Dirk Harms-Merbitz wrote:
We are currently seeing this first hand: Our real mail.power.net is at 207.151.19.8. The attacker is sending individualized emails with faked headers that contain "mail.power.net (unverified [209.26.14.22])".
The recipient computers are dumb enough to send their bounces to the real mail.power.net.
This is the problem - a mail server stupid enough to send a bounce to an unverified host name, instead of the connecting IP address.
This is a DOS because the innocent mail server a) gets millions of bounces and b) might get black listed on various "anti-spam" lists.
What anti-spam list maintainer would add an unverified host name in a header? Especially when the IP address does not match the hostname?
Dirk
TTFN, patrick -- I Am Not An Isp - www.ianai.net ISPF, The Forum for ISPs by ISPs, <http://www.ispf.com> "Think of it as evolution in action." - Niven & Pournelle (Enable? We dunt need no stinkin' enable!!)