From owner-freebsd-questions@FreeBSD.ORG Wed Nov 14 07:58:34 2007 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8998816A418 for ; Wed, 14 Nov 2007 07:58:34 +0000 (UTC) (envelope-from cpghost@cordula.ws) Received: from fw.farid-hajji.net (fw.farid-hajji.net [213.146.115.42]) by mx1.freebsd.org (Postfix) with ESMTP id 19EB213C504 for ; Wed, 14 Nov 2007 07:58:33 +0000 (UTC) (envelope-from cpghost@cordula.ws) Received: from epia-2.farid-hajji.net (epia-2 [192.168.254.11]) by fw.farid-hajji.net (Postfix) with ESMTP id A68EBE04C5; Wed, 14 Nov 2007 08:48:21 +0100 (CET) Date: Wed, 14 Nov 2007 08:48:18 +0100 From: cpghost To: Robert Huff Message-ID: <20071114084818.377cb6c8@epia-2.farid-hajji.net> In-Reply-To: <18234.26375.844671.397739@jerusalem.litteratus.org> References: <200711140234.lAE2Ykp9016352@banyan.cs.ait.ac.th> <18234.24690.239824.947693@jerusalem.litteratus.org> <18234.25217.475159.615201@jerusalem.litteratus.org> <18234.26375.844671.397739@jerusalem.litteratus.org> Organization: Cordula's Web X-Mailer: Claws Mail 3.0.2 (GTK+ 2.12.1; i386-portbld-freebsd6.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: questions@freebsd.org Subject: Re: How to reset a TCP connection X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Nov 2007 07:58:34 -0000 On Tue, 13 Nov 2007 22:09:59 -0500 Robert Huff wrote: > Robert Huff writes: > > > > Olivier Nicole writes: > > > > > > > How can I manually reset an established TCp connection? > > > > > > Ask Comcast. :-) > > My apologies for being cryptic. > In the United Stated, cable television and Internet provider > Comcast has recently come under criticism for "managing" bittorrent > traffic by sending TCP RST packets to those who are over some > unannounced traffic limit (i.e. hogging the bandwidth). This reminds me of an old bug ("sniper bug"): http://net.tamu.edu/tamunet/announce/1995/19950825-151018.html I've had a setup with those NICs on a university network in the '95, and those machines' TCP/IP stack kept wildly and seemingly randomly shooting down TCP connections between unrelated Unix hosts (sic!) with TCP RST packets (we've still had unswitched Ethernet, even a 10-base-5 yellow snake in the data center with a few PCs tapped on it). It nearly drove me nuts until I've intercepted and detected those spurious TCP RST packets with a sniffer (and at first, the sniffer machine had also one of those buggy NICs, go figure!) So Comcast is doing it all over again? Shooting down connections from the middle? Crazy nasty folks over there! A short-term fix is to filter out TCP RST packets at the firewall, and let TCP connections time out, even though it could waste a lot of kernel memory on busy nodes. cpghost. -- Cordula's Web. http://www.cordula.ws/