From owner-freebsd-hackers@FreeBSD.ORG Tue Jul 24 08:24:46 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 26F3F16A419 for ; Tue, 24 Jul 2007 08:24:46 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: from smtp808.mail.ird.yahoo.com (smtp808.mail.ird.yahoo.com [217.146.188.68]) by mx1.freebsd.org (Postfix) with SMTP id 789AE13C46C for ; Tue, 24 Jul 2007 08:24:45 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: (qmail 30678 invoked from network); 24 Jul 2007 08:24:44 -0000 Received: from unknown (HELO ?192.168.1.2?) (thomasjudge@btinternet.com@86.140.28.215 with plain) by smtp808.mail.ird.yahoo.com with SMTP; 24 Jul 2007 08:24:43 -0000 X-YMail-OSG: ovKbEdQVM1memgg6ztoQKUedOwv3i9LqQsvBufws8HPJwicLKxK3JkD.vKVzQ44pJPH2bioxxUOuQmCp9XTx8AOaXlksslwrGg-- Message-ID: <46A5C5B9.3000005@tomjudge.com> Date: Tue, 24 Jul 2007 10:26:17 +0100 From: Tom Judge User-Agent: Thunderbird 1.5.0.12 (X11/20070604) MIME-Version: 1.0 To: Jeremy Chadwick References: <46A5492E.90500@ispro.net> <20070724045054.GA81397@eos.sc1.parodius.com> In-Reply-To: <20070724045054.GA81397@eos.sc1.parodius.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Evren Yurtesen , freebsd-hackers@freebsd.org Subject: Re: alias netmask bug? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Jul 2007 08:24:46 -0000 Jeremy Chadwick wrote: > On Tue, Jul 24, 2007 at 03:34:54AM +0300, Evren Yurtesen wrote: >> I remember from earlier versions of FreeBSD that it had a restriction about >> alias IP netmasks (somewhere in 3.x,4.x days)... >> >> as explained here: >> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-virtual-hosts.html >> >> However I tried on the loopback interface to add a 2nd IP with the same >> netmask as the original IP and it accepts it fine. (on 6.2) >> >> lo0: flags=8049 mtu 16384 >> inet 127.0.0.1 netmask 0xff000000 >> inet 127.0.0.2 netmask 0xff000000 >> >> Is FreeBSD allowing this a bug or ??? > > It's not a bug. Why did you disregard the instructions, though? > >> If this is not a bug. What happens if an interface which is connecting to >> the machine has 2 IP addresses with same netmask which is not >> 255.255.255.255? Does FreeBSD use each IP randomly? > > Don't know, but my guess is no, it probably does not use "each IP > randomly", and I cannot even fathom the network breakage that would > ensue as a result of such. > I have seen systems that have been configured like this (on physical interfaces) have some strange problems. I'm sure one box that got a config like this by accident kicked one of the IP's off the interface several hours after it was set up. Never been able to reproduce that though. Tom