From owner-freebsd-stable@FreeBSD.ORG Tue Dec 19 17:05:29 2006 Return-Path: X-Original-To: freebsd-stable@FreeBSD.ORG Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D846C16A40F for ; Tue, 19 Dec 2006 17:05:29 +0000 (UTC) (envelope-from chris@vindaloo.com) Received: from corellia.vindaloo.com (corellia.vindaloo.com [64.51.148.100]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE19443CA8 for ; Tue, 19 Dec 2006 17:05:23 +0000 (GMT) (envelope-from chris@vindaloo.com) Received: from yavin.vindaloo.com (yavin.vindaloo.com [172.24.144.34]) by corellia.vindaloo.com (Postfix) with ESMTP id 84BDE5C6B for ; Tue, 19 Dec 2006 11:37:27 -0500 (EST) Received: from [172.24.145.69] (endor.vindaloo.com [172.24.145.69]) by yavin.vindaloo.com (Postfix) with ESMTP id 1DDE2253A8; Tue, 19 Dec 2006 11:37:27 -0500 (EST) Message-ID: <45881546.30400@vindaloo.com> Date: Tue, 19 Dec 2006 11:37:26 -0500 From: Christopher Hilton User-Agent: Thunderbird 1.5.0.8 (Macintosh/20061025) MIME-Version: 1.0 To: freebsd-stable@FreeBSD.ORG References: <200612191347.kBJDlg5c058711@lurza.secnetix.de> In-Reply-To: <200612191347.kBJDlg5c058711@lurza.secnetix.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: OpenBSD's spamd. X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Dec 2006 17:05:29 -0000 Oliver Fromme wrote: > Dimitry Andric wrote: > > Oliver Fromme wrote: > > > What does stuttering mean? Is it similar to sendmail's > > > "greet_pause" feature? > > > > See here: > > http://www.ualberta.ca/~beck/nycbug06/spamd/mgp00014.html > > OK, so the answer to my question seems to be "yes". :-) > Actually I'd say it's similar. If you telnet to port 25 on a server that's using sendmail's greet_pause option I'm assuming that you get nothing for 5 seconds. OpenSD's Spamd sends the initial greeting at a rate of one character per second and only accepts data from you at the same rate. Through experimentation Bob Beck determined that many spammers were dropping the connection and forgetting about delivering the mail completely after short and shorter intervals if the connection was rate limited to 1 character / sec. When the spammers got down to 3 seconds he modified spamd to stutter for 10 seconds on any connection. That feature came in on OpenBSD 3.8 -- Chris