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
[EMAIL PROTECTED] - The Power to Serve

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