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Date: Wed, 29 Nov 2000 20:53:32 -0800 (PST)
From: Mark Sutton <mes@capelazo.com>
To: linux-kernel@vger.kernel.org
Subject: TCP header bits set in reserved space
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Hi
	I can't seem to find this mentioned anywhere. My 2.4 machine
sets 2 bits in the TCP header between the 4 data offset bits and control 
flags. Like so:

11/29-20:25:42.695096 24.67.152.12:62373 -> 192.18.97.241:80
TCP TTL:63 TOS:0x0 ID:0  DF
21S***** Seq: 0x74E55D1A   Ack: 0x0   Win: 0x16D0
TCP Options => MSS: 1460 SackOK TS: 1767921 0 NOP WS: 0

or hex a0c2 / binary 10100000 11000010
			      ^^
This packet is never ACK'd by www.sun.com and the only difference I
can see from one that is are these two bits. RFC793 says they must be zero.
Is 793 still current? Has anyone else seen this?

Mark

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