From owner-freebsd-chat Wed Nov 26 10:01:06 1997 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.7/8.8.7) id KAA05529 for chat-outgoing; Wed, 26 Nov 1997 10:01:06 -0800 (PST) (envelope-from owner-freebsd-chat@FreeBSD.ORG) Received: from gratis.grondar.za (gratis.grondar.za [196.7.18.133]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id KAA05507; Wed, 26 Nov 1997 10:00:51 -0800 (PST) (envelope-from mark@greenpeace.grondar.za) Received: from greenpeace.grondar.za (Gm7WCtbcGqLLgClaRyQ7B6yaXtjUf7i3@greenpeace.grondar.za [196.7.18.132]) by gratis.grondar.za (8.8.7/8.8.8) with ESMTP id UAA07578; Wed, 26 Nov 1997 20:00:39 +0200 (SAT) (envelope-from mark@greenpeace.grondar.za) Received: from greenpeace.grondar.za (gRjP/VdW/cOIRB9ofhmGwkx5aQCZ3nQt@localhost [127.0.0.1]) by greenpeace.grondar.za (8.8.8/8.8.8) with ESMTP id UAA01100; Wed, 26 Nov 1997 20:00:37 +0200 (SAST) (envelope-from mark@greenpeace.grondar.za) Message-Id: <199711261800.UAA01100@greenpeace.grondar.za> X-Mailer: exmh version 2.0zeta 7/24/97 To: "Jonathan M. Bresler" cc: jkh@time.cdrom.com, grog@lemis.com, chat@hub.freebsd.org Subject: Re: major push by spammers? Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 26 Nov 1997 20:00:36 +0200 From: Mark Murray Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org "Jonathan M. Bresler" wrote: > > The stuff in FreeBSD's sendmail rules workds well, no doubt about that, > > but it is not failsafe. If your DNS is a bit slow, you can lose mail. > > hmm....not sure that i agree with you. > if w are slow to resolve, the error code is 451, a temp error, > meaning try again later. the spammers databases dont use DNS. > and RBL is failsafe.....so can you explain it to me? > > i dont understand. I'm looking at the rules again, and I'm confused. I have seen legitimate mail from freebsd/hub.freebsd.org being bounced with a 500 code when DNS was ropey. I cannot figure out this happened from the rules I have. I'll go with mea culpa unless proven otherwise :-). I meant: The ruleset that I have (committed by Peter?) looks up the domain of incoming mail. if it does not check, the mail is rejected. If the DNS does not answer in time, the mail is bounced for the same reason. Vixies RBL works in reverse; the spammer's IP is checked on connection. If the RBL resolves the IP (PTR-style) to 127.0.0.2 then the mail is rejected. If DNS fails, the mail is accepted by default. M -- Mark Murray Join the anti-SPAM movement: http://www.cauce.org