From owner-freebsd-stable Thu Oct 16 19:31:12 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id TAA11502 for stable-outgoing; Thu, 16 Oct 1997 19:31:12 -0700 (PDT) (envelope-from owner-freebsd-stable) Received: from freebie.dcfinc.com (freebie.dcfinc.com [138.113.2.8]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id TAA11487 for ; Thu, 16 Oct 1997 19:31:07 -0700 (PDT) (envelope-from chad@freebie.dcfinc.com) Received: (from chad@localhost) by freebie.dcfinc.com (8.8.3/8.8.3a) id TAA02679; Thu, 16 Oct 1997 19:28:47 -0700 (MST) From: "Chad R. Larson" Message-Id: <199710170228.TAA02679@freebie.dcfinc.com> Subject: Re: Anti-spam sendmail in 2.2.5? To: Don.Lewis@tsc.tdk.com (Don Lewis) Date: Thu, 16 Oct 1997 19:28:46 -0700 (MST) Cc: chad@dcfinc.com, root@eyelab.psy.msu.edu, dkelly@hiwaay.net, freebsd-stable@FreeBSD.ORG In-Reply-To: <199710170156.SAA27779@salsa.gv.tsc.tdk.com> from Don Lewis at "Oct 16, 97 06:56:16 pm" Reply-to: chad@dcfinc.com X-Mailer: ELM [version 2.4ME+ PL22 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-stable@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > On Oct 15, 10:07pm, "Chad R. Larson" wrote: > } Subject: Re: Anti-spam sendmail in 2.2.5? > > } Also under consideration is insisting on a HELO during the SMTP > } handshake and doing a DNS lookup on that system. If they don't match, > } you refuse the traffic. > > I'm pretty sure this isn't strictly legal according to the RFCs, and it > will probably block some non-spam mail. That's not to say it's not > effective against spam. > > --- Truck The biggest problem is the places where the name of the system as reported by HELO and it's name as reported by DNS can legitimately differ. For example, mail that has been through a proxy server, or a NAT. That's why it's "under consideration", instead of implemented. We might be evaluating the lessor of two evils. -crl -- Chad R. Larson (CRL22) Brother, can you paradigm? 602-953-1392 chad@dcfinc.com chad@anasazi.com crl22@aol.com DCF, Inc. - 14523 North 49th Place, Scottsdale, Arizona 85254