From owner-freebsd-doc Mon May 6 5:45:34 2002 Delivered-To: freebsd-doc@freebsd.org Received: from rhadamanth.submonkey.net (pc4-card4-0-cust162.cdf.cable.ntl.com [80.4.14.162]) by hub.freebsd.org (Postfix) with ESMTP id 0722137B404 for ; Mon, 6 May 2002 05:45:30 -0700 (PDT) Received: from setantae by rhadamanth.submonkey.net with local (Exim 3.36 #1) id 174hrs-00025c-00 for doc@FreeBSD.org; Mon, 06 May 2002 13:45:28 +0100 Date: Mon, 6 May 2002 13:45:28 +0100 From: Ceri Davies To: doc@FreeBSD.org Subject: Advanced Networking Question Message-ID: <20020506124528.GA7841@submonkey.net> Mail-Followup-To: Ceri Davies , doc@FreeBSD.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.28i Sender: owner-freebsd-doc@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Hi all, From the Advanced Networking chapter of the Handbook : Dual Homed Hosts dual homed hosts There is one other type of configuration that we should cover, and that is a host that sits on two different networks. Technically, any machine functioning as a gateway (in the example above, using a PPP connection) counts as a dual-homed host. But the term is really only used to refer to a machine that sits on two local-area networks. In one case, the machine has two Ethernet cards, each having an address on the separate subnets. Alternately, the machine may only have one Ethernet card, and be using &man.ifconfig.8; aliasing. The former is used if two physically separate Ethernet networks are in use, the latter if there is one physical network segment, but two logically separate subnets. Either way, routing tables are set up so that each subnet knows that this machine is the defined gateway (inbound route) to the other subnet. This configuration, with the machine acting as a Bridge <===== between the two subnets, is often used when we need to implement packet filtering or firewall security in either or both directions. Now I could be wrong, but I was under the impression that routing was a layer 3 function, and bridging was layer two, so isn't the statement that the machine is acting as a bridge incorrect (since it also states that the machine is doing routing) ? Thanks, Ceri -- get the cool shoe shine To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message