From owner-freebsd-hackers Thu Sep 19 01:48:20 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id BAA22729 for hackers-outgoing; Thu, 19 Sep 1996 01:48:20 -0700 (PDT) Received: from panda.hilink.com.au (panda.hilink.com.au [203.2.144.5]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id BAA22654 for ; Thu, 19 Sep 1996 01:48:11 -0700 (PDT) Received: (from danny@localhost) by panda.hilink.com.au (8.7.6/8.7.3) id SAA05892; Thu, 19 Sep 1996 18:48:08 +1000 (EST) Date: Thu, 19 Sep 1996 18:48:07 +1000 (EST) From: "Daniel O'Callaghan" To: freebsd-hackers@freebsd.org Subject: TCP extensions breaking TCP. Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk In /etc/sysconfig there is a comment # # Some broken implementations can't handle the RFC 1323 and RFC 1644 # TCP options. If TCP connections randomly hang, try disabling this, # and bug the vendor of the losing equipment. # tcp_extensions=YES The only times I have found these connections to hang are in connecting to other FreeBSD boxes. Last year, a particular 2.0.5 user could not exchange mail with me, and yesterday, a 2.1.5 user could not establish any TCP connections with any of my 2.0.5 or 2.1.5 machines. In the incident last year, the other party turned off tcp extensions, and all worked. This time, *I* turned off the extensions. Question is: why is this only being seen between FreeBSD boxes? I can quite happily talk amongst a network of around 10 FreeBSD machines with OS versions of 2.0.5, 2.1.0R, 2.1.0-stable, 2.1.5R, but suddenly there is a FreeBSD 2.1.5 machine I can't talk to. Does anyone have any ideas regarding what the other party or I have done wrong to wind up in this state. If people would like to test out the other machine (still has extensions on, I believe) it is at pixel.planetx.com.au - try telnetting to its smtp port. One of my machines which has extensions on, and which won't talk to pixel, is tutu.schools.net.au. If anyone can suggest a cause, I'm happy to attempt to do some debugging on this, if pointed in the right direction. Danny