Date: Tue, 12 Jun 2001 14:21:11 -0700 From: Peter Wemm <peter@wemm.org> To: Jesper Skriver <jesper@skriver.dk> Cc: Brian Dean <bsd@bsdhome.com>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/netinet tcp_timer.c Message-ID: <20010612212111.615AE380C@overcee.netplex.com.au> In-Reply-To: <20010612213636.A14059@skriver.dk>
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Jesper Skriver wrote: > On Tue, Jun 12, 2001 at 01:49:04PM -0400, Brian Dean wrote: > > On Tue, Jun 12, 2001 at 09:15:08AM -0700, Jesper Skriver wrote: > > > jesper 2001/06/12 09:15:08 PDT > > > > > > Modified files: (Branch: RELENG_4) > > > sys/netinet tcp_timer.c > > > Log: > > > MFC rev 1.44 > > > > > > Disable rfc1323 and rfc1644 TCP extensions if we havn't got > > > any response to our third SYN to work-around some broken > > > terminal servers (most of which have hopefully been retired) > > > that have bad VJ header compression code which trashes TCP > > > segments containing unknown-to-them TCP options. > > > > Do you know which terminal server brands and models might be broken in > > this respect? > > What I know is in <http://www.FreeBSD.org/cgi/query-pr.cgi?pr=1689>, > where Wollman say such beasts exist. > > But the work'around seems like a logical step. > > /Jesper Really old firmware versions of Annex and Xyplex are the culprits I believe. I'm also under the impression that fixed firmware for the annex at least was released years ago. The problem was that they applied van jacobson tcp header compression without checking to see if there were any options. On the other side, reassembly lead to checksum errors since the options got lost. The simplest fix for people dialing up through these antique boxes is to simply refuse van jacobson compression and you're clear. VJ compression cannot compress tcp headers with options anyway. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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