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Bugtraq archives for 2nd quarter (Apr-Jun) 1995: sequence numbers in TCP RST's (was Re: Watcher page moved)

sequence numbers in TCP RST's (was Re: Watcher page moved)

Vern Paxson (vernee.lbl.gov)
Sat, 01 Apr 95 17:03:17 PST

> 	 1) should TCP check the sequence number to avoid RST bombs?
> 
> Not only should but must, and I think does; see RFC 793.

It may be that most TCP's check sequence number of RST's.  I thought
I'd add, though, that there are plenty of TCP implementations which
don't bother to put the correct sequence number into RST's they generate.
I know this because I do a lot of TCP connection analysis by tracing
SYN/FIN/RST packets, and I have to special-case the RST packets in
my scripts because their sequence numbers are often bogus.

		Vern