From owner-freebsd-hackers Thu Sep 19 06:01:46 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id GAA16805 for hackers-outgoing; Thu, 19 Sep 1996 06:01:46 -0700 (PDT) Received: from Kitten.mcs.com (Kitten.mcs.com [192.160.127.90]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id GAA16780 for ; Thu, 19 Sep 1996 06:01:42 -0700 (PDT) Received: from mailbox.mcs.com (Mailbox.mcs.com [192.160.127.87]) by Kitten.mcs.com (8.8.Beta.4/8.8.Beta.3) with SMTP id IAA21397; Thu, 19 Sep 1996 08:01:32 -0500 (CDT) Received: by mailbox.mcs.com (/\==/\ Smail3.1.28.1 #28.15) id ; Thu, 19 Sep 96 08:01 CDT Received: (from karl@localhost) by Jupiter.Mcs.Net (8.8.Beta.3/8.8.Beta.3) id IAA24016; Thu, 19 Sep 1996 08:01:31 -0500 (CDT) From: Karl Denninger Message-Id: <199609191301.IAA24016@Jupiter.Mcs.Net> Subject: Re: TCP extensions breaking TCP. To: danny@panda.hilink.com.au (Daniel O'Callaghan) Date: Thu, 19 Sep 1996 08:01:31 -0500 (CDT) Cc: freebsd-hackers@freebsd.org In-Reply-To: from "Daniel O'Callaghan" at Sep 19, 96 06:48:07 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text 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 Win95 blows chunks if these are enabled and the connection comes in over an Ethernet (say, from an ISDN user). -- -- Karl Denninger (karl@MCS.Net)| MCSNet - The Finest Internet Connectivity http://www.mcs.net/~karl | T1 from $600 monthly; speeds to DS-3 available | 23 Chicagoland Prefixes, 13 ISDN, much more Voice: [+1 312 803-MCS1 x219]| Email to "info@mcs.net" WWW: http://www.mcs.net/ Fax: [+1 312 248-9865] | Home of Chicago's only FULL Clarinet feed!