Path: utzoo!attcan!uunet!ogicse!ucsd!ucbvax!SH.CS.NET!jcurran
From: jcurran@SH.CS.NET (John Curran)
Newsgroups: comp.protocols.tcp-ip
Subject: UDP Checksumming of IP addresses
Message-ID: <9011070014.AA08334@ucbvax.Berkeley.EDU>
Date: 6 Nov 90 20:55:01 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 8

I'm sure I've overlooked something, and could use a push..
 
Why does UDP (when used with checksumming enabled) create a pseudo-header 
that contains both the port numbers and the source and destination IP 
addresses?  Isn't it already protected from address changes by the datagram
checksum?

/John