From owner-freebsd-net@FreeBSD.ORG Fri Jun 20 08:56:24 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9AF45106567A for ; Fri, 20 Jun 2008 08:56:24 +0000 (UTC) (envelope-from prvs=10578ae54d=peter@teamspeak-systems.de) Received: from mail.teamspeak-systems.de (mail.teamspeak-systems.de [62.146.63.83]) by mx1.freebsd.org (Postfix) with ESMTP id 1B3A18FC1B for ; Fri, 20 Jun 2008 08:56:23 +0000 (UTC) (envelope-from prvs=10578ae54d=peter@teamspeak-systems.de) DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=teamspeak-systems.de; s=MDaemon; t=1213951561; x=1214556361; q=dns/txt; h=DomainKey-Signature:Received:From:To:Subject:Date: User-Agent:Organization:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-Disposition:Message-Id; bh=XPt mAtA8zfxcfmAcstSNWIBaHEWN9bTOPsGJD/3qALg=; b=pzBfZRmpGzyT8EbXQgE NEETHSAYPMXVOtrMmXiJGuL9H02B/OEpjndG7UwxxlaOrYAxWmscicg9ZWZPlSsA V/I/T9UXyBumuG7CEEe6THvbXTU+Of6DKQW6AwdVu6Q9whmwRer6LyG+mUDwJOTP /5z4gCnFCU7FWecFbF1203og= DomainKey-Signature: a=rsa-sha1; s=MDaemon; d=teamspeak-systems.de; c=simple; q=dns; h=from:message-id; b=Dsdd7TbKxoyuTWaO4yJAEQj0+ewrJPssUEePq9ryveI9ttA9dHdgvdteYwyp 7bD0r6SVkF4QAP4uJFkIhfwm5STdLemSol0j3cJbYQDX5MwJCr4YbWoGv 2Fj+ej84oS7RSwyK9MQ2m4M/q+SlaxBtfjGamBtZGaqVLgjt1naaZ8=; Received: from [192.168.2.101] by mail.teamspeak-systems.de (Cipher TLSv1:RC4-MD5:128) (MDaemon PRO v9.6.6) with ESMTP id 51-md50000006866.msg for ; Fri, 20 Jun 2008 10:46:01 +0200 X-Spam-Processed: mail.teamspeak-systems.de, Fri, 20 Jun 2008 10:46:01 +0200 (not processed: message from trusted or authenticated source) X-MDPtrLookup-Result: pass dns.ptr=p54AC88D3.dip0.t-ipconnect.de (ip=84.172.136.211) (mail.teamspeak-systems.de) X-MDHeloLookup-Result: hardfail smtp.helo=[192.168.2.101] (does not match 84.172.136.211) (mail.teamspeak-systems.de) X-Authenticated-Sender: peter@teamspeak-systems.de X-HashCash: 1:20:080620:md50000006866::vC3CxH2gHVgoZ5P1:00000M5m X-MDRemoteIP: 84.172.136.211 X-Return-Path: prvs=10578ae54d=peter@teamspeak-systems.de X-Envelope-From: peter@teamspeak-systems.de X-MDaemon-Deliver-To: freebsd-net@freebsd.org From: Peter Kirk To: freebsd-net@freebsd.org Date: Fri, 20 Jun 2008 10:46:00 +0200 User-Agent: KMail/1.9.7 Organization: TeamSpeak Systems MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200806201046.05530.peter@teamspeak-systems.de> X-MDAV-Processed: mail.teamspeak-systems.de, Fri, 20 Jun 2008 10:46:01 +0200 Subject: UDP checksum invalid on FreeBSD7/x86 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Jun 2008 08:56:24 -0000 Hi there, first of, this is my first posting to this list, hopfully it is the right place, if not please direct me, I was not being thick intentionally. I have a fresh installation of FreeBSD7 on x86, with no big changes to the system. Situation: Two PCs, one running linux and my own programs client application one running freebsd7 and my own programs server application The client and server of my program interchange UDP packets of various sizes. The problem I see is that small packets sent from the FreeBSD PC to the Linux PC are sent with an invalid UDP checksum (verified via tcpdump on the linux box). In my tests all packets with less than 30 bytes UDP payload had an invalid checksum set. All packets with more than 15 bytes had the correct checksum set. So, the "exact" number should be somewhere between 15 and 30 bytes. The receiving Linux box discards the packets with invalid checksums, which of course is problematic for my applications well-being. To "fix" the problem I did: sudo sysctl -w net.inet.udp.checksum=0 This doesn't seem to be a real fix, but more a work-around. If any more information (regarding my installation, my hardware or how my application uses the networking functions) is required, just ask. Thanks in advance for your responses. PS: I also tried with the client application on other operating systems than linux (e.g. win32), and the same problem occured, so this does seem to be a freebsd issue. Peter -- Today is the first day of the rest of your life.