[3460] in bugtraq
Re: Excellent host SYN-attack fix for BSD hosts
daemon@ATHENA.MIT.EDU (Vern Paxson)
Tue Oct 15 01:29:00 1996
Date: Mon, 14 Oct 1996 10:18:23 PDT
Reply-To: Vern Paxson <vern@ee.lbl.gov>
From: Vern Paxson <vern@ee.lbl.gov>
X-To: Granville Moore <granville_moore@il.us.swissbank.com>
To: Multiple recipients of list BUGTRAQ <BUGTRAQ@NETSPACE.ORG>
In-Reply-To: Your message of Mon, 14 Oct 1996 13:31:47 PDT.
> I don't understand why window scaling would be a problem, since the window
> size isn't included in the MD5 ...
Because the window scaling option is not included in any packets other than
the initial SYN. So if you don't remember it from when the SYN is first
seen, you have no way to recover it. The goal is to not keep any state
around, so the scale has to be buried in the munged sequence number.
Vern
