Wireshark-dev: [Wireshark-dev] TCP window size incorrect when a filter is applied.
From: "Maynard, Chris" <Christopher.Maynard@xxxxxxxxx>
Date: Thu, 13 Sep 2007 12:20:57 -0400
I opened a bug #1842 for this:
http://bugs.wireshark.org/bugzilla/show_bug.cgi?id=1842, but here's the
bug description:

Build Information:
SVN 22858
--
The TCP window size, as displayed in the Info column for SYN-ACK
packets, is
incorrect if a TCP conversation filter is applied.  This can easily be
seen
using the small 3 packet trace file I will attach.  If you open the file
with
no filter applied, the correct unscaled window size of 5792 is reported;
however, you right-click and choose "Conversation Filter -> TCP", then
the
window size is incorrectly reported as 2965504, which means that the
scaling
factor of 9 (multiply by 512) is incorrectly being applied.  As you
probably
already know, the scaling factor should never be applied to window sizes
for
SYN or SYN-ACK packets.   If you didn't know that, then refer to the
last
paragraph of section 2.2 in RFC1323, available here:
http://www.ietf.org/rfc/rfc1323.txt


Actually, it seems that if any display filter is applied, then the
problem
occurs.  And if the filter is cleared, the window size is still
incorrect
afterwards.

- Chris

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