From owner-freebsd-questions@FreeBSD.ORG Wed Jul 30 14:20:30 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 F3362106566C for ; Wed, 30 Jul 2008 14:20:30 +0000 (UTC) (envelope-from keramida@freebsd.org) Received: from igloo.linux.gr (igloo.linux.gr [62.1.205.36]) by mx1.freebsd.org (Postfix) with ESMTP id 75EC88FC1B for ; Wed, 30 Jul 2008 14:20:30 +0000 (UTC) (envelope-from keramida@freebsd.org) 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 m6UEKBpj028886 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 30 Jul 2008 17:20:18 +0300 Received: from kobe.laptop (kobe.laptop [127.0.0.1]) by kobe.laptop (8.14.2/8.14.2) with ESMTP id m6UEKAsv050699; Wed, 30 Jul 2008 17:20:10 +0300 (EEST) (envelope-from keramida@freebsd.org) Received: (from keramida@localhost) by kobe.laptop (8.14.2/8.14.2/Submit) id m6UEK9rm050698; Wed, 30 Jul 2008 17:20:09 +0300 (EEST) (envelope-from keramida@freebsd.org) From: Giorgos Keramidas To: perryh@pluto.rain.com References: <488fe865.x7NyNic2A5pcZPCL%perryh@pluto.rain.com> <87ljzkdm3x.fsf@kobe.laptop> <87hca8dlh3.fsf@kobe.laptop> <489013b9.Pt7+7kznBXs3SSP+%perryh@pluto.rain.com> Date: Wed, 30 Jul 2008 17:20:08 +0300 In-Reply-To: <489013b9.Pt7+7kznBXs3SSP+%perryh@pluto.rain.com> (perryh@pluto.rain.com's message of "Wed, 30 Jul 2008 00:09:45 -0700") Message-ID: <874p67xxlz.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: m6UEKBpj028886 X-Hellug-MailScanner: Found to be clean X-Hellug-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-4.718, required 5, autolearn=not spam, ALL_TRUSTED -1.80, AWL -0.32, BAYES_00 -2.60) X-Hellug-MailScanner-From: keramida@freebsd.org X-Spam-Status: No Cc: 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 14:20:31 -0000 On Wed, 30 Jul 2008 00:09:45 -0700, perryh@pluto.rain.com wrote: >>>> 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. >>> >>> Setting the interface MTU should do it, i.e.: >>> >>> ifconfig re0 mtu 640 >>> >>> Not all interfaces support setting the MTU and some may have range >>> restrictions though. >> >> In particular, this seems to work with my wlan0 interface, but not >> with my re0 interface ... > > That's certainly simple enough, and xl0 apparently supports the > reduced mtu setting. It seems to be working just fine. Thanks! > > I'd thought of trying to set the sun's MTU, but hadn't been able > to find a way to do it. It had never occurred to me that setting > the *recipient's* MTU would limit the *sender's* packet size. You can edit `/etc/hostname.foo0' in the Sun too, and add something like: 192.168.1.10/24 mtu 640 but since now you are happy with the new setup, that's fine :)