John, John Polstra wrote: > You are running tcpdump on the system that's sending the "bad" > packets, right? It makes perfect sense. The TCP/IP stack knows > that the NIC is going to insert the checksums, so it doesn't bother > calculating them itself. So BPF is handed packets in mbufs without > any checksums. On the way out to the wire, the NIC hardware/firmware > adds the checksums, but they don't show up in the mbufs that are being > sent to BPF. If you run tcpdump on the receiving system instead, > you'll find that the checksums seen there are valid. > > The same thing happens in the bge driver, because it also offloads > checksum generation to the NIC.
that makes total sense. I'd like to see the paragraph above in big, bold letters in the xl(4) man page then - so far it doesn't discuss checksum offloading at all. :-) Thanks, Lars -- Lars Eggert <[EMAIL PROTECTED]> Information Sciences Institute http://www.isi.edu/larse/ University of Southern California
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