Date: Thu, 10 Feb 2005 13:28:52 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Sam Jansen <sam@meta.net.nz> Cc: freebsd-net@freebsd.org Subject: Re: SACK problems Message-ID: <20050210212852.GA10195@xor.obsecurity.org> In-Reply-To: <420BCEF7.1080603@meta.net.nz> References: <420BCEF7.1080603@meta.net.nz>
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--UlVJffcvxoiEqYs2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 11, 2005 at 10:15:35AM +1300, Sam Jansen wrote: > During some testing on an isolated network we have, I found some=20 > interesting behaviour from a FreeBSD 5.3 host using TCP SACK. >=20 > I've detailed this problem fully at: >=20 > http://www.wand.net.nz/~stj2/nsc/emu_freebsd.html >=20 > PCAP traces and some screenshots from tcptrace graphs can be found at=20 > the above link to show what is happening. It looks to me like SACK=20 > blocks are being incorrectly generated in this example. I can't think of= =20 > any valid reason why a SACK block would SACK from below the current ACK= =20 > value to above it (which is the problem here). >=20 > Thoughts, anyone? Am I just wrong here and this is valid, expected=20 > behaviour? A fix to the SACK code was committed yesterday, which may or may not be relevant. Kris --UlVJffcvxoiEqYs2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFCC9IUWry0BWjoQKURAnpyAJ9Z8R6ydGjhdKCqpt+zPuCC/0K9qACePnEX D/fZFvFAiL1m8Af2l+pMJjg= =kW8D -----END PGP SIGNATURE----- --UlVJffcvxoiEqYs2--
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