From: gah@ugcs.caltech.edu   
      
   In comp.dcom.lans.ethernet Jorgen Grahn  wrote:   
   (snip)   
      
   > UDP-based protocols keep state too, and are just as picky about where   
   > the datagram came from as TCP. You cannot expect every datagram to   
   > contain full context, so the application protocol uses the source   
   > address:port (and maybe destination too) as a key to lookup state for   
   > the "conversation".   
      
   Some UDP protocols are picky, but most aren't.  TCP identifies   
   a connection by the quad   
   source-address:source-port:destination-address:destination-port.   
      
   Many UDP protcols/implementations will accept anything coming   
   into the appropriate port.   
      
   I once had a NAT router that could be configured to send the   
   address translated packets out the originating port.  When it   
   did that, it didn't translate the source port, so the replies   
   would go directly to the originator, instead of back through   
   the NAT router.  That worked with UDP, but not TCP.   
   (The specific system I was using was SunRPC based.  I believe   
   it works with all SunRPC based protocols.)   
      
   -- glen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)