Re: [lwip-users] UDP packet sending problem

[Yoshiki Komatsudaira]

I don't think the UDP checksum is invalid.
It maybe come from "Checksum offloading".
http://www.wireshark.org/docs/wsug_html_chunked/ChAdvChecksums.html


Subject: Re: [lwip-users] UDP packet sending problem
From: patrick Deflandre

> I am wondering too why my linux station send bad checksum on a few ip
> frame. I don't know if it change something on my problem, but I should
> investigate on that problem too.
> 
> Nevertheless, as the udp frame seem to be received by the target, I
> don't think this is the problem for sending an udp frame from the
> embedded lwIP to my linux station.
> Does anybody knows about linux bad checksum of ip frame ?
> 
> 2009/6/26 Bill Auerbach <address@hidden>
> 
> >  Could it be the checksum error?
> >
> >
> >
> > User Datagram Protocol, Src Port: 41486 (41486), Dst Port: tftp (69)
> >     Source port: 41486 (41486)
> >     Destination port: tftp (69)
> >     Length: 13
> >     Checksum: 0x3333 [incorrect, should be 0x419b (maybe caused by "UDP
> > checksum offload"?)]
> >         [Good Checksum: False]
> >         [Bad Checksum: True]
> > Trivial File Transfer Protocol
> >     Opcode: Unknown (28777)
> >     Data (3 bytes)