From owner-freebsd-net Mon Jan 27 17:17:44 2003 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C505537B401; Mon, 27 Jan 2003 17:17:43 -0800 (PST) Received: from great4.greatschools.net (great4.greatschools.net [199.4.104.154]) by mx1.FreeBSD.org (Postfix) with ESMTP id 61B7A43F3F; Mon, 27 Jan 2003 17:17:43 -0800 (PST) (envelope-from jdd@greatschools.net) Received: from great4.greatschools.net (localhost [127.0.0.1]) by great4.greatschools.net (8.12.6/8.12.6) with ESMTP id h0S1Hhuc007224; Mon, 27 Jan 2003 17:17:43 -0800 (PST) (envelope-from jdd@greatschools.net) Received: from localhost (jdd@localhost) by great4.greatschools.net (8.12.6/8.12.6/Submit) with ESMTP id h0S1HgvE007221; Mon, 27 Jan 2003 17:17:42 -0800 (PST) X-Authentication-Warning: great4.greatschools.net: jdd owned process doing -bs Date: Mon, 27 Jan 2003 17:17:37 -0800 (PST) From: John David Duncan To: freebsd-current@freebsd.org, freebsd-net@freebsd.org Subject: Direct Server Return and FreeBSD 5 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org There's a load balancing configuration known as direct server return (DSR), in which packets pass from the client through the load balancer to the server, but then the replies from the server go directly to the client (bypassing the load balancer). The way this works is that the load balancer sends the server an IP packet with the virtual IP address as its destination addr, inside an ethernet frame whose destination is the real MAC addr of the server. The server replies with a normal packet using the VIP as the source addr. The usual way to configure a BSD box to work this way is to bring up the VIP as an alias on the loopback address, like this: ifconfig lo0 add 1.2.3.4 netmask 0xffffff00 As far as I can tell from my testing, this trick just doesn't work on my box running -CURRENT. In tcpdump I see packets coming in but none going out. Does anybody know why, or what I would have to do to change the behavior? - JD To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message