From: gah@ugcs.caltech.edu   
      
   Rick Jones  wrote:   
   (snip on IPv4 vs IPv6 and UDP checksum)   
      
   > That might be more accurately put as IPv6 does not include an IP   
   > *header* checksum - someone reading "packet checksum" might mistakenly   
   > conclude the IPv4 header checksum includes the data of the IP   
   > datagram.  The checksum in IPv4 only covers the IPv4 header, to verify   
   > that there were no bit errors in the header.   
      
   I remember the discussions some years ago on Sun running   
   NFS with UDP checksum turned off.  The suggestion was that ethernet   
   checksum would apply, and verify that the data was correct.  NFS was,   
   and probably still is, mostly used on LANs, and rarely WANs.   
   Most often with no router in between, maybe at most one, and   
   ethernet all the way.  At that time (68020 Sun3) the time to calculate   
   and verify the checksum might have been significant, but should be   
   much less significant today.   
      
   > With a mandatory UDP checksum (I'm sure the streaming types like   
   > that...) when going over IPv6 you can still get misdirected IPv6   
   > datagrams, but ostensibly some of them will be tossed at the   
   > destination when they get to UDP and the UDP checksum fails thanks to   
   > the inclusion of the "pseudo header" (IIRC).   
      
   > IMO it is a perfect example of the sway the "router guys" had in   
   > defining IPv6 - now they have no IP header checksum to check or   
   > otherwise worry about.   
      
   -- glen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)