[H-GEN] How to block this kind of email?

[Sarah Walters]

Hi all,

I am using sendmail with no spam filtering backend (i.e. no spamassassin, etc). It delivers to a Cyrus mailstore, if you care.

This morning I received the following email. It's very clearly a virus, and I obviously wasn't stupid enough to open the attachment.

Surely I can configure sendmail to reject mail from a server that *claims* to be walters.id.au, and isn't? Please help me out here.

Thanks,
Sarah Walters

===

Return-Path: <webmaster at walters.id.au>
Received: from onyx.walters.id.au ([unix socket])
	 by onyx.walters.id.au (Cyrus v2.2.12) with LMTPA;
	 Tue, 07 Mar 2006 06:34:47 +1000
X-Sieve: CMU Sieve 2.2
Received: from walters.id.au (CPE-144-137-159-43.qld.bigpond.net.au [144.137.159.43])
	by onyx.walters.id.au (8.13.4/8.13.4) with ESMTP id k26KYfhH047997
	for <sarah at walters.id.au>; Tue, 7 Mar 2006 06:34:41 +1000 (EST)
	(envelope-from webmaster at walters.id.au)
Message-Id: <200603062034.k26KYfhH047997 at onyx.walters.id.au>
From: webmaster at walters.id.au
To: sarah at walters.id.au
Subject: *WARNING* Your Email Account Will Be Closed
Date: Tue, 7 Mar 2006 06:32:40 +1000
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="----=_NextPart_000_0006_A279A049.6D2A8605"
X-Priority: 3
X-MSMail-Priority: Normal

This is a multi-part message in MIME format.

------=_NextPart_000_0006_A279A049.6D2A8605
Content-Type: text/plain;
	charset="Windows-1252"
Content-Transfer-Encoding: 7bit

We regret to inform you that your account has been suspended due to the violation of our site policy, more info is attached.