On Tue, Oct 17, 2006 at 10:24:41PM -0700, David Cuthbert wrote: > I'm puzzled. Why block the Comcast SMTP server instead of just the > Comcast dynamic IP block? The zombies are highly unlikely to try to use > the official SMTP server.
They are in fact very likely to use it. Many spamming viruses have their
own SMTP implementation and send directly, but an increasing number uses
MAPI and will simply take over the SMTP settings from Outlook, including
smarthost and even SMTP authentication.
Geert
