From owner-freebsd-questions@FreeBSD.ORG Wed Jul 30 22:22:01 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 C34511065673 for ; Wed, 30 Jul 2008 22:22:01 +0000 (UTC) (envelope-from keramida@ceid.upatras.gr) Received: from igloo.linux.gr (igloo.linux.gr [62.1.205.36]) by mx1.freebsd.org (Postfix) with ESMTP id 4167A8FC13 for ; Wed, 30 Jul 2008 22:22:00 +0000 (UTC) (envelope-from keramida@ceid.upatras.gr) Received: from kobe.laptop (adsl151-101.kln.forthnet.gr [62.1.242.101]) (authenticated bits=128) by igloo.linux.gr (8.14.3/8.14.3/Debian-5) with ESMTP id m6UMLYjL031628 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 31 Jul 2008 01:21:46 +0300 Received: from kobe.laptop (kobe.laptop [127.0.0.1]) by kobe.laptop (8.14.2/8.14.2) with ESMTP id m6UMLYwO077031; Thu, 31 Jul 2008 01:21:34 +0300 (EEST) (envelope-from keramida@ceid.upatras.gr) Received: (from keramida@localhost) by kobe.laptop (8.14.2/8.14.2/Submit) id m6UMLQKi077030; Thu, 31 Jul 2008 01:21:26 +0300 (EEST) (envelope-from keramida@ceid.upatras.gr) From: Giorgos Keramidas To: Derek Ragona References: <488fe865.x7NyNic2A5pcZPCL%perryh@pluto.rain.com> <6.0.0.22.2.20080730155021.024dd828@mail.computinginnovations.com> Date: Thu, 31 Jul 2008 01:21:25 +0300 In-Reply-To: <6.0.0.22.2.20080730155021.024dd828@mail.computinginnovations.com> (Derek Ragona's message of "Wed, 30 Jul 2008 16:20:06 -0500") Message-ID: <87abfzxbbu.fsf@kobe.laptop> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-MailScanner-ID: m6UMLYjL031628 X-Hellug-MailScanner: Found to be clean X-Hellug-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-4.009, required 5, autolearn=not spam, ALL_TRUSTED -1.80, AWL 0.39, BAYES_00 -2.60) X-Hellug-MailScanner-From: keramida@ceid.upatras.gr X-Spam-Status: No Cc: perryh@pluto.rain.com, freebsd-questions@freebsd.org Subject: Re: setting the other end's TCP segment size 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, 30 Jul 2008 22:22:01 -0000 On Wed, 30 Jul 2008 16:20:06 -0500, Derek Ragona wrote: > At 11:04 PM 7/29/2008, perryh@pluto.rain.com wrote: >> > [TCP] splits traffic to 'segments' using its own logic ... >> >> Is there a simple way for a FreeBSD system to cause its peer to use a >> transmit segment size of, say, 640 bytes -- so that the peer will >> never try to send a packet larger than that? >> >> I'm trying to get around a network packet-size problem. In case it >> matters, the other end is SunOS 4.1.1 on a sun3, and I've been unable >> to find a way to limit its packet size directly. > > Just as an FYI, you might want to do: > man setsockopt > ro > man getsockopt > > Each tcp conversation can have it's own size set along with a bunch of > other params. Good point. The TCP_MAXSEG can reduce the maximum segment size for a single TCP connection to something smaller than the interface MTU :)