From owner-freebsd-current Tue May 14 11:15:55 2002 Delivered-To: freebsd-current@freebsd.org Received: from mailsrv.otenet.gr (mailsrv.otenet.gr [195.170.0.5]) by hub.freebsd.org (Postfix) with ESMTP id 26F5437B400 for ; Tue, 14 May 2002 11:15:50 -0700 (PDT) Received: from hades.hell.gr (patr530-a012.otenet.gr [212.205.215.12]) by mailsrv.otenet.gr (8.12.3/8.12.3) with ESMTP id g4EIFh1b029571; Tue, 14 May 2002 21:15:44 +0300 (EEST) Received: from hades.hell.gr (hades [127.0.0.1]) by hades.hell.gr (8.12.3/8.12.3) with ESMTP id g4EIFg83006715; Tue, 14 May 2002 21:15:46 +0300 (EEST) (envelope-from keramida@ceid.upatras.gr) Received: (from charon@localhost) by hades.hell.gr (8.12.3/8.12.3/Submit) id g4EHUbDu006363; Tue, 14 May 2002 20:30:37 +0300 (EEST) (envelope-from keramida@ceid.upatras.gr) Date: Tue, 14 May 2002 20:30:36 +0300 From: Giorgos Keramidas To: Cristan Szmajda Cc: current@FreeBSD.ORG Subject: Re: bad tcp cksum fffe! Message-ID: <20020514173036.GF5715@hades.hell.gr> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.99i Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 2002-05-14 17:39, Cristan Szmajda wrote: > Dear freebsd-current, > > Any suggestions you have regarding this problem would be > much appreciated. > > My laptop running -CURRENT is suddenly generating bad TCP > checksums when talking to some IPs but not others. For > example, 129.94.209.220 is a problem, > > 17:08:47.026823 129.94.233.200.1032 > 129.94.209.220.22: S > [bad tcp cksum fffe!] 3868790363:3868790363(0) win 65535 > > (DF) (ttl 64, id 347, len 68) I've seen this only twice. The first time I was using too funky optimizations to the CFLAGS of my kernel, and GCC was obviously doing something wrong with the checksum generation code. If this is the case, then rebuild your kernel and userland with the suggested optimizations from /usr/share/examples/etc/make.conf and see if this fixes things for you. The second one was when my tcpdump (and the rest of the userland) was really VERY out of sync with the running kernel (I had managed to upgrade only the kernel and tcpdump was probably reading random data from bpf). But there were other more important things wrong with this case. -- Giorgos Keramidas - http://www.FreeBSD.org keramida@FreeBSD.org - The Power to Serve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message