I didn't mean for that to sound as bad as it did. As I had said in the first e-mail I made the same mistake you did originally. I sent Leonid an e-mail directly (nasty habit of hitting the reply instead of reply all button) and was wrong when I said it. But then I remembered I had some issues calculating the checksum and went to look at my source to jog my memory and saw that my memory was wrong as well. I was going to let it stand at that, but I didn't want incorrect information left on the list after your initial reply. No hard feelings either way I hope. Who are we to question the wisdom of the designers of TCP? :) On topic to Leonid, you can calculate the TCP checksum using the algorithm on that website I posted a minute ago. I'm surprised you actually calculated the IP checksum, normally the stack does that automatically before it goes out (if it wasn't in your case I would like to hear specifics of what you are doing for my own interest). -----Original Message----- From: Antony Stone [mailto:Antony@xxxxxxxxxxxxxxxxxxxx] Sent: Friday, November 21, 2003 15:14 To: netfilter@xxxxxxxxxxxxxxxxxxx Subject: Re: Checksumming Issues On Friday 21 November 2003 9:00 pm, Hildebrand, Brian wrote: > www.netfor2.com/tcpsum.htm > > That is the first website I found. I'm sure if you look some more you could > probably find about 500 more. If you do not follow those instructions, you > will get bad checksum returns. Just because it is an OSI layer higher does > not mean it can't include data from lower down the chain. You are right. The TCP checksum contains a "notional IP header" which is included in the calculation. Today is not a good day for me :( It must be somebody else's birthday. Antony. -- I love deadlines. I love the whooshing noise they make as they go by. - Douglas Noel Adams Please reply to the list; please don't CC me. ---------------------------------------- The information transmitted in this message is intended only for the person or entity to whom it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and destroy any copies of this document.
