Subject: Re: Bad TCP checksum error

From: Rick Jones <[email-masked]>
Date: Fri, 26 Oct 2007 09:59:16 -0700

Checksum Offload on the NIC(s) can complicate things.  First, if you are tracing 
on the sender, the tracepoint is before the NIC has computed the full checksum. 
  IIRC only a partial checksum is passed-down to the NIC when CKO is in use.

So, making certain your trace is from the "wire" or the receiver rather than the 
sender would be a good thing, and trying again with CKO disabled on the 
interface(s) (via ethtool) might be something worth looking at.  Ultimately, 
doing the partial checksum modificiations in a CKO-friendly manner might be a 
good thing.

rick jones