Date: Tue, 14 May 2002 20:30:36 +0300 From: Giorgos Keramidas <keramida@FreeBSD.ORG> To: Cristan Szmajda <cls@cse.unsw.edu.au> Cc: current@FreeBSD.ORG Subject: Re: bad tcp cksum fffe! Message-ID: <20020514173036.GF5715@hades.hell.gr> In-Reply-To: <Pine.GSO.4.44.0205141701170.805-100000@mozart.orchestra.cse.unsw.EDU.AU> References: <Pine.GSO.4.44.0205141701170.805-100000@mozart.orchestra.cse.unsw.EDU.AU>
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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 > <mss 1460,nop,wscale 1,nop,nop,timestamp 542813 0,nop,nop,ccnew 10> > (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
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