From owner-freebsd-questions@FreeBSD.ORG Sun Mar 25 13:33:19 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 986F416A404 for ; Sun, 25 Mar 2007 13:33:19 +0000 (UTC) (envelope-from smithi@nimnet.asn.au) Received: from gaia.nimnet.asn.au (nimbin.lnk.telstra.net [139.130.45.143]) by mx1.freebsd.org (Postfix) with ESMTP id 1C9A913C458 for ; Sun, 25 Mar 2007 13:33:17 +0000 (UTC) (envelope-from smithi@nimnet.asn.au) Received: from localhost (smithi@localhost) by gaia.nimnet.asn.au (8.8.8/8.8.8R1.5) with SMTP id XAA26552; Sun, 25 Mar 2007 23:33:08 +1000 (EST) (envelope-from smithi@nimnet.asn.au) Date: Sun, 25 Mar 2007 23:33:07 +1000 (EST) From: Ian Smith To: Richard In-Reply-To: <20070324120023.91CC916A4D6@hub.freebsd.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: freebsd-questions@freebsd.org Subject: [OT] Re: TCP conection problems IBM VM -> FreeBSD 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: Sun, 25 Mar 2007 13:33:19 -0000 On Sat, 24 Mar 2007 07:40:50 -0400 Richard reckons: [..] > Then I started thinking (always a fruitless endeavor), why would a *BSD > based firewall/"IP stack" drop the corresponding SYN-ACK when it was > activated? And that thought just fucking bugged me to no end. I could > accept some crazy IBM "IP stack" not dealing with *BSD, but this was > *BSD box to *BSD box on the return path that dropped the packet. Also, > according to the original poster bang.swox.se has no problems > communicating with other systems and he has no problems communicating to > vm.se.lsoft.com. I can't help with the Real Problem here, hence Subject change, but .. [..] > ** After looking through "Stevens TCP/IP Illustrated" I can find no > reference to what sequence number a RST packet should have if a SYN-ACK > precedes it. I'm unsure whether the RST should ACK the SYN + 1, as a > SYN consumes a byte in normal operation, or return the ISN to the > sending host. But as sending a RST in response to a SYN-ACK is not > normal operation; such ambiguities would likely be left to the > programmers discretion. In this case IBM not a stack derived from *BSD. Secondly, the IBM TCP/IP stack and most userland network utilities were declaredly BSD-derived at least through the '90s OS/2 times - and likely much earlier, but I've not played with an IBM mainframe since '73 :) But firstly, I wonder why you'd expect IBM to run 'some crazy' stack? > this now opens a whole new box of worms?!?!? Hopefully not .. Cheers, Ian