Date: Fri, 12 Aug 2011 17:43:09 -0400 From: Chip Marshall <chip@2bithacker.net> To: freebsd-net@freebsd.org Subject: Odd TCP RFC1323 Behavior Message-ID: <20110812214309.GI72508@2bithacker.net>
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--jQIvE3yXcK9X9HBh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable I've been digging into an issue with SSH throughput and discovered that one of the servers involved isn't using RFC1323 window scaling and timestamps. The server is running 7.3-RELEASE-p3, and has net.inet.tcp.rfc1323 set to 1. When connecting out from the server, it sets both Window Scale and TimeStamp options in the SYN packet and everything is fine. When a connection comes into the server with WS and TS set in the SYN, the response varies. For port 53 (named) the SYN/ACK has WS/TS options. For port 22 (sshd) the SYN/ACK does not have WS/TS options, unless the connection is via lo0. ssh is OpenSSH_5.2p1, compiled from ports with default options. I'm really at a loss to explain this. Why does named use RFC1323 on bce0 when sshd doesn't? Why does sshd use RFC1323 on lo0 but not on bce0? I can provide PCAPs of the SYN, SYN/ACK exchanges if that will help. --=20 Chip Marshall <chip@2bithacker.net> http://weblog.2bithacker.net/ KB1QYW PGP key ID 43C4819E v4sw5PUhw4/5ln5pr5FOPck4ma4u6FLOw5Xm5l5Ui2e4t4/5ARWb7HKOen6a2Xs5IMr2g6CM --jQIvE3yXcK9X9HBh Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (Darwin) iEYEARECAAYFAk5Fnm0ACgkQnTUxIUPEgZ73qgCdF1xpXXVOzs6UjSe09mKsba/y 5yQAoLmj2cyE5/DrMIDz85pg7tqjWx2I =yC3U -----END PGP SIGNATURE----- --jQIvE3yXcK9X9HBh--
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