On Aug 10, 2004, at 3:32 PM, Douglas Otis wrote:
The Not Authorized aspect of CSV-CSA was intended only to offer added
protection, should a system be considered vulnerable to being
compromised. Such as a system may provide web or shell services, but
is
not intended to be sending mail. A specific removal of this host from
being authorized adds additional protections from Trojans.
Actually, the Not Authorized CSV record doesn't help against Trojans:
Those mailers are never going to use the infected host's domain name in
HELO/EHLO.
What would help is simply blocking outgoing port 25 access for those
hosts. In fact this is much more effective: The receiving MTA doesn't
have to support CSV for it to work! If I were a sys. admin., that's
what I'd do.
- Mark
Mark Lentczner
http://www.ozonehouse.com/mark/
markl(_at_)glyphic(_dot_)com