On Friday 21 November 2003 8:42 pm, Hildebrand, Brian wrote:
> I had to check my packet generator source code, because I thought the TCP
> header was calculated the same way you do. But when I checked the source
> you have to feed both the TCP and IP headers into the calculation to get a
> correct checksum. It uses some information from the IP header in the
> calculation (source and destination IP for example). So you don't actually
> use the entire IP header, just a part of it.
It is not possible that the TCP checksum depends on IP information.
TCP is layer 4 of the OSI model; IP is layer 3. The IP checksum includes
the TCP contents, but not the other way around.
Antony.
--
There's no such thing as bad weather - only the wrong clothes.
- Billy Connolly
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