From owner-freebsd-hackers@FreeBSD.ORG Tue Jul 24 07:50:07 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 1C61316A417 for ; Tue, 24 Jul 2007 07:50:07 +0000 (UTC) (envelope-from yurtesen@ispro.net) Received: from mail.ispro.net (mail.ispro.net [87.251.0.19]) by mx1.freebsd.org (Postfix) with SMTP id 038AD13C478 for ; Tue, 24 Jul 2007 07:50:05 +0000 (UTC) (envelope-from yurtesen@ispro.net) Received: (qmail 93937 invoked by uid 399); 24 Jul 2007 10:50:04 +0300 Received: from unknown (HELO ?84.250.38.203?) (yurtesen@ispro.net@84.250.38.203) by mail.ispro.net with ESMTP; 24 Jul 2007 10:50:04 +0300 X-Originating-IP: 84.250.38.203 Message-ID: <46A5AEED.4080104@ispro.net> Date: Tue, 24 Jul 2007 10:49:01 +0300 From: Evren Yurtesen User-Agent: Thunderbird 1.5.0.12 (Windows/20070509) 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: 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 07:50:07 -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? I didnt disregard the instructions. I read somebody suggesting not using 255.255.255.255 in some forum. Then I tried it out and FreeBSD accepted the netmask for the alias IP. Why does FreeBSD accept such netmask which can cause problems when earlier it was rejecting it? >> 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 understand, I will try to test that sometime to see what FreeBSD does in this kind of situation. However, it might be nice if ifconfig did not allow this kind of wrong setting. Thanks, Evren