IP-Checksum question - TCP-IP

This is a discussion on IP-Checksum question - TCP-IP ; Does anyone of you know whether it is possible to icrementally adjust the IP-checksum when adjusting the TTL-field, i.e. to compute the checksum according to the changes made in the packet? Thanks in advance...

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Thread: IP-Checksum question

  1. IP-Checksum question

    Does anyone of you know whether it is possible to icrementally
    adjust the IP-checksum when adjusting the TTL-field, i.e. to
    compute the checksum according to the changes made in the packet?

    Thanks in advance

  2. Re: IP-Checksum question

    In article <468a5489$0$20997$9b4e6d93@newsspool1.arcor-online.net>,
    Elcaro Nosille wrote:
    >Does anyone of you know whether it is possible to icrementally
    >adjust the IP-checksum when adjusting the TTL-field, i.e. to
    >compute the checksum according to the changes made in the packet?


    It is.

    Good luck on the rest of your homework!


    --
    Daniel L. McDonald - Solaris Security & Networking Engineering
    Mail: danmcd@sun.com | * MY OPINIONS ARE NOT NECESSARILY SUN'S! *
    1 Network Drive Burlington, MA |"rising falling at force ten
    http://blogs.sun.com/danmcd/ | we twist the world and ride the wind" - Rush

  3. Re: IP-Checksum question

    Elcaro Nosille wrote:

    > Does anyone of you know whether it is possible to incrementally
    > adjust the IP-checksum when adjusting the TTL-field, i.e. to
    > compute the checksum according to the changes made in the packet?


    Err, did you try Google?

    e.g. http://www.google.com/search?q=checksum+incremental

    Did you read RFC 1141 and RFC 1624?

    http://tools.ietf.org/html/rfc1141
    http://tools.ietf.org/html/rfc1624

  4. Re: IP-Checksum question

    Dan McDonald schrieb:

    >> Does anyone of you know whether it is possible to icrementally
    >> adjust the IP-checksum when adjusting the TTL-field, i.e. to
    >> compute the checksum according to the changes made in the packet?


    > It is.
    > Good luck on the rest of your homework!


    This wasn't my homework; just a question I asked myself.

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