Blocking on HELO (was Re: [Mimedefang] filter_relay)
lambert at jeol.com
Mon Nov 1 11:55:11 EST 2004
On Mon, 1 Nov 2004, David F. Skoll wrote:
> That's true. But a very narrow block can block a lot of spam. My mail
> server (mail.roaringpenguin.com) has IP address 18.104.22.168.
> The maillog covers about 36 hours. That means that more than once an hour,
> some random host claims to be *my* IP address (22.214.171.124) in its HELO.
> I block all of those and haven't had a complaint yet.
As do I. Blocking HELO claiming to be my domain works well also.
> (If you were pedantic, you'd block a host that uses any kind of naked
> IP address in HELO, because it really should use [ip.addr.of.host]
> with the square brackets.)
I tried that but rejected good email from a few broken mail servers. :-(
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