Date: Tue, 4 Feb 1997 21:10:20 +1100 (EST) From: proff@suburbia.net To: hackers@freebsd.org Subject: linux net killer or no idea? (fwd) Message-ID: <19970204101020.12479.qmail@suburbia.net>
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>From richard@a42.deep-thought.org Mon Feb 03 23:36:52 1997 Return-Path: <richard@a42.deep-thought.org> Delivered-To: proff@suburbia.net Received: (qmail 24578 invoked from network); 3 Feb 1997 23:36:51 -0000 Received: from a42.deep-thought.org (203.4.184.227) by suburbia.net with SMTP; 3 Feb 1997 23:36:51 -0000 Received: from a42.deep-thought.org ([127.0.0.1]) by a42.deep-thought.org with esmtp id m0vrXwh-0024w0C (Debian Smail-3.2 1996-Jul-4 #2); Tue, 4 Feb 1997 10:37:07 +1100 (EST) Message-Id: <m0vrXwh-0024w0C@a42.deep-thought.org> X-Mailer: exmh version 1.6.9 8/22/96 To: proff@suburbia.net Subject: linux net killer or no idea? Date: Tue, 04 Feb 1997 10:37:07 +1100 From: Richard Jones <richard@a42.deep-thought.org> ------- Forwarded Message Return-Path: owner-linux-net-outgoing@vger.rutgers.edu Return-Path: <owner-linux-net-outgoing@vger.rutgers.edu> Received: from suburbia.net ([203.4.184.1]) by a42.deep-thought.org with smtp id m0vrXBE-0024w0a (Debian Smail-3.2 1996-Jul-4 #2); Tue, 4 Feb 1997 09:48:04 +1100 (EST) Received: (qmail 3224 invoked from network); 3 Feb 1997 21:47:35 -0000 Received: from nic.funet.fi (128.214.248.6) by suburbia.net with SMTP; 3 Feb 1997 21:47:35 -0000 Received: from vger.rutgers.edu ([128.6.190.2]) by nic.funet.fi with ESMTP id <55330-6926>; Mon, 3 Feb 1997 18:50:20 +0200 Received: by vger.rutgers.edu id <214100-245>; Mon, 3 Feb 1997 11:35:54 -0500 To: linux-net@vger.rutgers.edu Cc: dash@linpro.no Subject: The file that kills linux tcp From: Arnt Gulbrandsen <agulbra@troll.no> Date: 03 Feb 1997 17:37:24 +0100 Message-ID: <m3ohe13kxn.fsf@lupinella.troll.no> Lines: 43 X-Mailer: Gnus v5.2.25/XEmacs 19.14 Sender: owner-linux-net@vger.rutgers.edu Precedence: bulk This is the weirdest problem I've ever, ever seen. Or so it feels like. I've just seen machines running linux/2.0.27, linux/2.1.24 and freebsd/3.0-current freeze after downloading 144540 bytes of this file: ftp://ftp.troll.no/contrib/xppp1B-x86-ELF.tar.gz Many clients can download this file just fine, many others can not. Those who can't all freeze after exactly 144540 bytes. A file of the same size but with different contents works. The same file with a different name does not work. The same file recompressed (zcat | gzip - -9) to be 600 bytes smaller can be downloaded by everyone as far as I can test. The same file recompressed (-5) to be 2100 bytes larger too. The FTP daemon is troll-ftpd 1.20 running on linux 2.0.26 and then on 2.0.28. The same file _can_ be downloaded from the same version of troll-ftpd running on a different linux box, which runs 2.0.27. There are no tcp-related changes between .27 and .28, as far as I can see. A huge tcpdump packet trace showing first a successful transfer of a 384604-byte file, then the one which freezes is available at ftp://ftp.troll.no/tmp/thud The two transfers look much the same to me, except that there appears to be a single packet loss while the window is wide-open, and the connection never recovers if this crucial file is being transferred. I don't know which of several netstat lines -t correspond to the packet trace. The most likely one shows a send queue of 43880 bytes, the others are similar. I don't know whether the file, the ftpd or the packet trace helps. Should anyone feel like tracing something so weird and need other data, or access to the box, do write. (Please cc any replies to me - I don't read linux-net right now, and probably won't for another two weeks or so.) - --Arnt ------- End of Forwarded Message
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