Date: Sat, 17 Mar 2001 10:28:25 -0600 (CST) From: Nick Rogness <nick@rogness.net> To: freebsd-net@FreeBSD.ORG Cc: Jeroen Ruigrok/Asmodai <asmodai@wxs.nl> Subject: Re: same interface Route Cache Message-ID: <Pine.BSF.4.21.0103171002500.16887-100000@cody.jharris.com> In-Reply-To: <3AB3882D.5EAC34@softweyr.com>
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On Sat, 17 Mar 2001, Wes Peters wrote: [Wes, if you get this, for some reason I can't send to your domain.] You are not understanding what I am trying to say. Once again I'll try to clarify. > > For dual-homed hosts, this is a problem because your packet gets > > sent out the default gateway, which may or may not get filtered > > upstream. This is usually solved by running a routing deamon but > > most upstreams won't allow you to do that anyway (cable,dsl,etc). > > If you have a dual-homed host that is simply routing an internal LAN to > the external network, you don't need anything other than a default route. > If it's not bound for the internal network, it goes to the external > network, by definition. > Actually, that is not what "dual-homed" in the internet world means. Dual homed is having 2 *public* Internet connections. That's ISP lingo. > I completely fail to see that you have actually stated a problem yet. > > What exactly is the problem you think you're trying to solve here? > Consider the following. I have to restate this every damn couple of weeks to get it through. Here is the problem: ISP#1 ISP#2 | | | | --- xl0 FreeBSD xl1 ----- xl2 | | Internal network | | Machine 1 Packet 1 comes in through ISP #2 network. It comes into your internal network to machine 1. Machine 1 replies to the packet...but where does it go? It will exit through interface to ISP #1 because of the default gateway. It came in ISP #2 and left out ISP #1. There is your problem. What if you are running nat in this case....your hosed. You can check out route-cache at Cisco's online site. It may help to clarify as to why you would want to do this. If you check the -net mailing list this problem re-occurs over and over and over and over and over. To which there is a work around that's a bit messy. Nick Rogness <nick@rogness.net> - Keep on routing in a Free World... "FreeBSD: The Power to Serve!" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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