What's this mean?

Bill Moran wmoran at potentialtech.com
Sat Jun 28 11:36:30 PDT 2003

budsz wrote:
> Hi dude,
> I get message in /var/log/message:
> /kernel: in_cksum: out of data by 3
> Would you explain this message? 

in_chksum is a routine that validates the checksum of recieved network data.
As far as I can tell from the code, that error means that the packet of data
was three bytes shorter than it should have been.  One way or the other it's
a network problem.  Could be crappy NIC or other hardware.  Could be some sort
of attack using invalid packets.  I'm not familiar enough with that corner of
the code to say for sure.
Is this happening frequently?  If you only saw the message once, you can
probably ignore it as a network glitch, but if it's showing up often, you'd
do well to track down the source and fix it.

Bill Moran
Potential Technologies

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