RELENG-7 tcp connectivity problems with certain clients

[Erik Trulsson]

On Fri, Mar 07, 2008 at 05:53:37PM -0600, David DeSimone wrote:
> Jake Rizzo <rizzojake at gmail.com> wrote:
> >
> > 16:04:31.445390 IP (tos 0x20, ttl 109, id 41184, offset 0, flags [DF], proto
> > TCP (6), length 48) xxxxx.comcastbusiness.net.22625 > 192.168.1.104.http: S,
> > cksum 0x81e2 (correct), 3539746141:3539746141(0) win 16384 <mss
> > 1380,nop,nop,sackOK>
> > 16:04:31.445405 IP (tos 0x0, ttl 64, id 55077, offset 0, flags [DF], proto
> > TCP (6), length 48, bad cksum 0 (->b21)!) 192.168.1.104.http >
> > xxxxx.comcastbusiness.net.22625: S, cksum 0x58a4 (incorrect (-> 0x8f6e),
> 
> tcpdump is pointing out some bad checksums in your outgoing packets.

Yes, of course it does, since tcpdump sees the packet before the card has
filled in the checksum.  This will always happen whenever you use tcpdump
with a NIC that has hardware checksums enabled.


> 
> Maybe you should try ifconfig -txcsum?



-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at student.uu.se