From owner-freebsd-questions@FreeBSD.ORG Thu Aug 7 09:52:38 2003 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1B79A37B401 for ; Thu, 7 Aug 2003 09:52:38 -0700 (PDT) Received: from munk.nu (213-152-51-194.dsl.eclipse.net.uk [213.152.51.194]) by mx1.FreeBSD.org (Postfix) with ESMTP id 66A7143FA3 for ; Thu, 7 Aug 2003 09:52:37 -0700 (PDT) (envelope-from munk@munk.nu) Received: from munk by munk.nu with local (Exim 4.20) id 19ko0C-0003BN-Ig for questions@freebsd.org; Thu, 07 Aug 2003 17:52:36 +0100 Date: Thu, 7 Aug 2003 17:52:36 +0100 From: Jez Hancock To: questions@freebsd.org Message-ID: <20030807165236.GB11607@users.munk.nu> Mail-Followup-To: questions@freebsd.org References: <3F326499.50501@401.cx> <0D9C0182-C8F5-11D7-A4DD-0030656DD690@foolishgames.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0D9C0182-C8F5-11D7-A4DD-0030656DD690@foolishgames.com> User-Agent: Mutt/1.4.1i Sender: User Munk Subject: Re: ISPs blocking SMTP connections from dynamic IP address space X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Aug 2003 16:52:38 -0000 On Thu, Aug 07, 2003 at 12:34:45PM -0400, Lucas Holt wrote: > > > > I think we need software that blocks spam out of the box. > > Server Side: > I've found that most of my time is spent installing addons for sendmail > to do virus scanning and spam prevention. Why don't mail servers have > spam assassin, black lists, etc. enabled and installed with a base set > of rules to prevent spam? Every release of the software would also > need to include new rules, but your ip list solution needs updating all > the time too. Exim with exiscan enabled allows you to reject mail considered spam based on the results of an SA scan. The hard part is maintaining a decent blacklist locally if you can't afford the overhead of using online RBL blacklist servers on a heavily used mail server I would imagine. Another issue with this is what you tell your clients. I recently had a client who I recommended to a certain ISP who received an email from that ISP which was nothing short of scare-mongering. The email was written by the CEO of the ISP, who it appears hadn't a clue about exactly how the software blocked spam or perhaps wasn't that good at articulating in layman's terms exactly how spam was to be blocked. As a result a number of the ISP's clients were instantly worried that anything containing swear words or 'make money' or whatever in the subject would be blocked, which wouldn't be the case (one would hope!). I think a nice alternative is to set a number of different filtering rules on the MTA so that spam that scores very highly (say over 15 on the SA scale) is rejected outright, whereas spam that scores relatively highly on the SA scale has it's subject modified to indicate that the content is possibly spam. Again though this could be seen as unwanted intrusion by some customers... -- Jez http://www.munk.nu/