From owner-freebsd-net@FreeBSD.ORG Mon Feb 18 22:15:18 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3912316A421 for ; Mon, 18 Feb 2008 22:15:18 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: from tomjudge.vm.bytemark.co.uk (tomjudge.vm.bytemark.co.uk [80.68.91.100]) by mx1.freebsd.org (Postfix) with ESMTP id D23D713C467 for ; Mon, 18 Feb 2008 22:15:17 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: from localhost (localhost [127.0.0.1]) by tomjudge.vm.bytemark.co.uk (Postfix) with ESMTP id 21A9B34186; Mon, 18 Feb 2008 22:15:16 +0000 (GMT) Received: from tomjudge.vm.bytemark.co.uk ([127.0.0.1]) by localhost (tomjudge.vm.bytemark.co.uk [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id NxoNw0Qw2uLz; Mon, 18 Feb 2008 22:15:15 +0000 (GMT) Received: from [192.168.255.6] (unknown [192.168.255.6]) by tomjudge.vm.bytemark.co.uk (Postfix) with ESMTP id 7EE8B34178; Mon, 18 Feb 2008 22:15:14 +0000 (GMT) Message-ID: <47BA037A.8010405@tomjudge.com> Date: Mon, 18 Feb 2008 16:15:22 -0600 From: Tom Judge User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Bill Moran References: <38308.1203368454@thrush.ravenbrook.com> <20080218163618.5e6672d3.wmoran@collaborativefusion.com> <6xiZ7xvVdDqVhj0EdhE90pfdIcQ@S1JitD8kpKQ9sTxL7Qyzy/kv7rU> <20080218170642.e079540d.wmoran@collaborativefusion.com> In-Reply-To: <20080218170642.e079540d.wmoran@collaborativefusion.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Nick Barnes , freebsd-net@freebsd.org Subject: Re: Multiple default routes on multihome host X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Feb 2008 22:15:18 -0000 Bill Moran wrote: > In response to Eygene Ryabinkin : > >> Bill, >> >> Mon, Feb 18, 2008 at 04:36:18PM -0500, Bill Moran wrote: >>> I would suggest you ask yourself (and possibly the list) _why_ you think >>> multiple default routes is necessary ... what is it that you're hoping >>> to accomplish. I'm guessing your looking for some sort of redundancy, >>> in which case something like CARP or RIP is liable to be the correct >>> solution. >> I had faced such situation once: I had multihomed host that was >> running Apache daemon that was announced via two DNS names that >> were corresponding to two different IPs, going via two different >> providers. When the first provider's link goes down, the second >> provider is still alive, and when both providers are alive, the >> traffic is balanced via DNS round-robin alias. Do you see some >> better way to do it via CARP, RIP, something different? I am still >> interested in other possibilities. > > The canonical way to do this is with BGP. I can be done with CARP > if both providers support it and are willing to work together. > Unfortunately businesses tend to get bundled PA address space when purchasing leased lines off of ISP. This means that a some what simple transition from provider A to provider B can not be done with BGP. Also as the OP states one the the address blocks that he has is a /25 which most ISP's will filter from the BGP address table because it is to small. I think the cost of learning BGP, getting an AS number and a suitable large block of PI address space, getting 2 routers that can do BGP, coupled with the consultancy costs charged by the ISP to setup the BGP feed totally out way the cost of just multihoming a box for a few days/weeks while the required changes take affect.. Ok so this is not ideal but hey it works and its simpler.. Just my 2c Tom