Re: TCP checksum and device driver eri0

From: Martin Paul (martin_at_par.univie.ac.at)
Date: 06/30/03

  • Next message: Casper Dik: "Re: TCP checksum and device driver eri0"
    Date: Mon, 30 Jun 2003 10:20:49 +0200 (MEST)
    To: focus-sun@securityfocus.com
    
    

    > During a snoop session on a 280R with solaris 9 and network interface
    > eri0, I noticed that the TCP checksum field of every outgoing packet was
    > incorrect.
    > ...
    > The same packet snooped on the network has the correct checksum value.
    > I believe that something happens between the snoop point on the machine
    > and the network interface eri0 output.

    I guess that's the same effect that's described in the ethereal FAQ at:

      http://www.ethereal.com/faq.html#q5.8
      
    It's because the checksum is added to the packet by the network
    interface, and not by the TCP/IP stack.

    mp.

    -- 
                             Martin Paul | Systems Administrator
          Institute for Software Science | martin@par.univie.ac.at
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            http://www.par.univie.ac.at/ | Fax: 01 4277 9388
    

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