Many TCP/IP packages with incorrect checksums - HP UX

This is a discussion on Many TCP/IP packages with incorrect checksums - HP UX ; Hello. Recently I noticed, that a lot of the TCP/IP packages generated by our HP-UX 11.00 and 11.11 systems have a wrong checksum. At least that's shown, when I open the nettl trace generated by running nettl -tn pduin pduout ...

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Thread: Many TCP/IP packages with incorrect checksums

  1. Many TCP/IP packages with incorrect checksums

    Hello.

    Recently I noticed, that a lot of the TCP/IP packages
    generated by our HP-UX 11.00 and 11.11 systems have
    a wrong checksum.

    At least that's shown, when I open the nettl trace generated
    by running

    nettl -tn pduin pduout -tm 20000 -e ns_ls_ip -f /tmp/nettl

    in Ethereal.

    The ratio of packages with wrong checksums is close to
    50%.

    I'm hesitating to make such a trace file publically available,
    as it might contain passwords or other sensitive data.

    Is this something that I need to worry about?

    Alexander Skwar
    --
    She's genuinely bogus.


  2. Re: Many TCP/IP packages with incorrect checksums

    Do these happen to be outbound TCP segments (ie segments being sent by
    the same machine on which Ethereal is running)? If so, are the NICs
    GbE NICs? If so, what you are likely seeing is the effect of the
    checksum calcultion being offloaded to the NIC and not an actual
    incorrect checksum.

    rick jones
    --
    denial, anger, bargaining, depression, acceptance, rebirth...
    where do you want to be today?
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  3. Re: Many TCP/IP packages with incorrect checksums

    ยท Rick Jones :

    > Do these happen to be outbound TCP segments (ie segments being sent by
    > the same machine on which Ethereal is running)?


    Yes, they are.

    > If so, are the NICs
    > GbE NICs?


    Correct again

    > If so, what you are likely seeing is the effect of the
    > checksum calcultion being offloaded to the NIC and not an actual
    > incorrect checksum.


    Thanks a lot.

    Now, how do I give you points for this answer?

    Alexander Skwar

  4. Re: Many TCP/IP packages with incorrect checksums

    >> If so, what you are likely seeing is the effect of the
    >> checksum calcultion being offloaded to the NIC and not an actual
    >> incorrect checksum.


    > Thanks a lot.


    > Now, how do I give you points for this answer?


    The ones in the HP ITRC forums will suffice

    rick jones
    --
    portable adj, code that compiles under more than one compiler
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

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