From owner-freebsd-questions@FreeBSD.ORG Wed Aug 27 17:37:42 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5D642106567B for ; Wed, 27 Aug 2008 17:37:42 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout013.mac.com (asmtpout013.mac.com [17.148.16.88]) by mx1.freebsd.org (Postfix) with ESMTP id 536CE8FC14 for ; Wed, 27 Aug 2008 17:37:42 +0000 (UTC) (envelope-from cswiger@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Received: from cswiger1.apple.com ([17.227.140.124]) by asmtp013.mac.com (Sun Java(tm) System Messaging Server 6.3-7.03 (built Aug 7 2008; 32bit)) with ESMTPSA id <0K69006IZSY0J670@asmtp013.mac.com> for freebsd-questions@freebsd.org; Wed, 27 Aug 2008 10:37:12 -0700 (PDT) Message-id: From: Chuck Swiger To: Peter Ulrich Kruppa In-reply-to: <48B566EA.2000406@pukruppa.net> Date: Wed, 27 Aug 2008 10:37:11 -0700 References: <48B566EA.2000406@pukruppa.net> X-Mailer: Apple Mail (2.928.1) Cc: FreeBSD-Questions Subject: Re: Spam sent to me from my own mail server ? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Aug 2008 17:37:42 -0000 On Aug 27, 2008, at 7:38 AM, Peter Ulrich Kruppa wrote: > for some time now I keep receiving spam mails from my own (small) > mail server, some of them with faked usernames some of them even > with my own (ulrich@...). > 1) How is this possible? Forging email headers is trivial. You can do it with telnet by hand, although spammers tend to use malware which blasts lots of messages.... > 2) What can I or do I have to do against it? > I am running a quite plain sendmail setup from 7.0 -STABLE. Configuring anti-spam measures is something that would occupy a book. For starters, look into greylisting, RBLs, and anti-spam tools which hook into the milter interface. There's also some config-level changes documented here: http://www.sendmail.org/m4/anti_spam.html Regards, -- -Chuck