tcptrace-bugs tcptrace graphing errors when window scaling in effect

Date: 12/05/03

Subject: tcptrace-bugs tcptrace graphing errors when window scaling in effect
Date: Sat, 06 Dec 2003 00:26:11 +0000
Message-Id: <>

Hi there,

I am using tcptrace to plot tcp connections which have the window scaling option enabled. tcptrace cannot correctly determine the true window size since the scaling factor is only exchanged at tcp session initiation and my traces do not contain the initial 3-way handshake (I realize that the scaled window is properly displayed if the initial syn-ack is present in the trace).

This is probably more a feature request than a bug, but it would be nice if tcptrace had a command-line option which would allow a user to invoque it in 'window scaling mode' so that the resulting xplot could accurately trace the yellow line - the scaling factor couldbe passed as a parameter to tcptrace (actually, two parameters since the scaling factor can be different in each direction). This could possibly be implemented as an extended option such as:

-w_scale_x2y z

where x and y represent the various a2b, b2a, c2d, d2c, etc, and z is the scaling factor (for example, z=3 implies a scaling factor of 2^3, so the advertized receiver window on that connection should be multiplied by 8).

Thanks for an awesome tool!


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