From owner-freebsd-questions Sun Jan 18 07:38:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA15780 for questions-outgoing; Sun, 18 Jan 1998 07:38:39 -0800 (PST) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from didda.est.is (root@didda.est.is [194.144.208.205]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA15754 for ; Sun, 18 Jan 1998 07:38:28 -0800 (PST) (envelope-from totii@est.is) Received: from est.is (totii@didda.est.is [192.168.255.1]) by didda.est.is (8.8.7/8.8.7) with ESMTP id AAA17209; Sun, 18 Jan 1998 00:10:07 GMT (envelope-from totii@est.is) Message-ID: <34C1485E.977C0065@est.is> Date: Sun, 18 Jan 1998 00:10:06 +0000 From: Thordur Ivarsson X-Mailer: Mozilla 4.04 [en] (X11; I; FreeBSD 2.2.5-RELEASE i386) MIME-Version: 1.0 To: Dan Busarow CC: Font , questions@FreeBSD.ORG Subject: Re: MAIL FROM: address check commented out in /etc/mail additions? References: Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk Dan Busarow wrote: > > On Thu, 15 Jan 1998, Font wrote: > > closer examination I found that a line in sendmail.cf.additions had been > > commented out: > > > > # R $* < @ $+ > $#error $: "451 Domain does not resolve" > > > > I was just curious as to whether this was intentional (what are the > > disadvantages here? can some legit mail be rejected?) or just overlooked. > This rule is rather nasty: If sender has not legimate A record in name server the rule fails and sends back error, CNAME record is not enough for sender. > Can't tell you why the line is commented out but I can say that > since adding this our spam has gone *way* down. It catches several > hundred a day. More than any of the other anti-spam checks. > > I haven't checked in some time but I did monitor the logs closely > after installing it and only found one instance where it looked > like a legitimate, but misconfigured mailer. I contacted the > customer it was addressed to and asked if he knew how to get in > touch with the apparent sender and my customer said "those guys > have been spamming me" :) > > IOW, it really seems to work well. > -- Þórður Ívarsson Thordur Ivarsson Rafeindavirki Electronic technician Norðurgötu 30 Nordurgotu 30 Box 309 Box 309 602 Akureyri 602 Akureyri Ísland Iceland --------------------------------------------- FreeBSD has good features, Some others are full of unwanted features! ---------------------------------------------