Wireshark · Ethereal-dev: Re: [Ethereal-dev] TCP checksums

[Todd Sabin <tas@xxxxxxxxxxx>]

Mark Burton <markb@xxxxxxxxxx> writes:

> Folks,
> 
> I have discovered that if you capture packets under linux 2.4.4 from
> an 3c905c ethernet card, the TCP checksum is sometimes wrong. I don't
> understand what's going on in the kernel but I assume it's something
> to do with the fact that the card supports hardware checksumming.
> 

You're very likely seeing the effects of a bug in the linux kernel TCP
layer which was fixed in 2.4.6.  In certain cases, invalid TCP
checksums were generated.  You should upgrade your kernel.

See the following link for the whole story.

http://www.uwsg.iu.edu/hypermail/linux/kernel/0106.3/1194.html


Todd