Refusing mails from hosts w/o reverse DNS?

[Gerald Pfeifer]

I know that we already have quite effective anti-spam measures at work
on gcc.gnu.org, but how about another addition (which, from what I can
tell, works quite well):

How about rejecting mails from hosts w/o reverse DNS, such as the
following which just hit the gcc mailing list?

  Received: from unknown (HELO alarit.com) (213.154.192.40)
    by sources.redhat.com with SMTP; 17 Jul 2002 19:52:26 -0000

I know there may be false positive now and then (like one of Red Hat's
own servers earlier this year), but the Good Guys can easily fix this
configuration problem on their side, and it is really effective.

Gerald