Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!TOPAZ.RUTGERS.EDU!ron
From: ron@TOPAZ.RUTGERS.EDU (Ron Natalie)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Pseudo-Headers & Checksumming
Message-ID: <8801111640.AA16603@topaz.rutgers.edu>
Date: 11 Jan 88 16:40:15 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 8


You seem to imply that you can throw the IP addresses away when you
get to the TCP layer.  The TCP port numbers are only significant when
paired with the ip addresses as well.  You must remember this
information somewhere, so you need the pseudoheader.  Since the idea
of the checksum is to prevent insidious little errors that "can't"
happen (it's a little useless for error correction as it is a very
weak), you really want to cover all the relevent