From owner-freebsd-questions@FreeBSD.ORG Tue Sep 11 08:13:27 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 11B5116A41B for ; Tue, 11 Sep 2007 08:13:27 +0000 (UTC) (envelope-from nvass@teledomenet.gr) Received: from smtp.teledomenet.gr (smtp.teledomenet.gr [213.142.128.2]) by mx1.freebsd.org (Postfix) with ESMTP id CE5B013C4F0 for ; Tue, 11 Sep 2007 08:13:26 +0000 (UTC) (envelope-from nvass@teledomenet.gr) Received: by smtp.teledomenet.gr (Postfix, from userid 58) id 666841420D2; Tue, 11 Sep 2007 11:13:25 +0300 (EEST) X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on smtp.teledomenet.gr X-Spam-Level: X-Spam-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,RDNS_NONE autolearn=no version=3.2.3 Received: from iris (unknown [192.168.1.71]) by smtp.teledomenet.gr (Postfix) with ESMTP id 7DA7A14203B; Tue, 11 Sep 2007 11:13:22 +0300 (EEST) From: Nikos Vassiliadis To: freebsd-questions@freebsd.org Date: Tue, 11 Sep 2007 11:11:19 +0300 User-Agent: KMail/1.9.1 References: <5f65302543fd0f474c9994801c2c1517@prodigy.net> In-Reply-To: <5f65302543fd0f474c9994801c2c1517@prodigy.net> X-NCC-RegID: gr.telehouse MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709111111.20285.nvass@teledomenet.gr> Cc: jekillen Subject: Re: ip assignments 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: Tue, 11 Sep 2007 08:13:27 -0000 On Sunday 09 September 2007 21:50, jekillen wrote: [snio] > I found > that each of the interfaces have to be assigned an address > in a different subnet. for them to both be usable. > Q: Is this characteristic of tcp/ip in general, or specific > to FreeBSD? Imagine the following situation: NIC0 10.0.0.1/24 NIC1 10.0.0.2/24 The kernel gets a packet from 10.0.0.3. Where should the reply would be send from? NIC0 or NIC1? Situation #2 NIC0 10.0.0.1/24 NIC1 10.0.0.2/24 NIC2 192.168.0.1/24 The kernel gets a packet for 10.0.0.3. Where this packet should be forwarded to? So, FreeBSD does not accept such IP configurations, to keep things sane. Other operating systems accept such configurations, but you have to be careful and you have to know what you are doing, in order to prevent self foot-shooting. Of course there are valid ways to achieve the same results without the foot-shooting factor. Using aliases with /32 mask is one. What's wrong with IP_alias/32? HTH Nikos