From owner-freebsd-net Sat Apr 6 21:28:28 2002 Delivered-To: freebsd-net@freebsd.org Received: from rwcrmhc51.attbi.com (rwcrmhc51.attbi.com [204.127.198.38]) by hub.freebsd.org (Postfix) with ESMTP id DC15537B400 for ; Sat, 6 Apr 2002 21:28:24 -0800 (PST) Received: from blossom.cjclark.org ([12.234.91.48]) by rwcrmhc51.attbi.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with ESMTP id <20020407052824.YQMW18078.rwcrmhc51.attbi.com@blossom.cjclark.org>; Sun, 7 Apr 2002 05:28:24 +0000 Received: (from cjc@localhost) by blossom.cjclark.org (8.11.6/8.11.6) id g375SNe71336; Sat, 6 Apr 2002 21:28:23 -0800 (PST) (envelope-from cjc) Date: Sat, 6 Apr 2002 21:28:22 -0800 From: "Crist J. Clark" To: Nick Rogness Cc: "Matthew D. Fuller" , Alex Rousskov , freebsd-net@FreeBSD.ORG Subject: Re: Forcing packets to the wire Message-ID: <20020406212822.G70207@blossom.cjclark.org> References: <20020405222555.C65380@over-yonder.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from nick@rogness.net on Sat, Apr 06, 2002 at 01:57:44PM -0600 X-URL: http://people.freebsd.org/~cjc/ 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 On Sat, Apr 06, 2002 at 01:57:44PM -0600, Nick Rogness wrote: > On Fri, 5 Apr 2002, Matthew D. Fuller wrote: > > > On Fri, Apr 05, 2002 at 06:48:09PM -0600 I heard the voice of > > Nick Rogness, and lo! it spake thus: > > > On Fri, 5 Apr 2002, Alex Rousskov wrote: > > > > > > > > - Is it possible without kernel modifications? How? > > > > > > AFAIK, No. Your only 2 possiblities that I could think of would > > > be to use policy routing or natd. Both will fail in this case. > > > > You MIGHT be able to use ipfw divert/pipe rules to somehow shove the > > packets into a program on their way out, and write a program that > > would use raw sockets to hand-assemble the IP datagram on the way out; > > I'm not sure if the kernel would try to outsmart you on that. > > Yeh, I thought of that. The problem is packets never leave > anywhere since the route for the other NIC is not "OUT" any > interface...it is the machine itself. Then never go over a _physical_ inteface, but they _do_ cross an interface, lo0, the internal loopback. ipfw fwd ip from to in via lo0 -- Crist J. Clark | cjclark@alum.mit.edu | cjclark@jhu.edu http://people.freebsd.org/~cjc/ | cjc@freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message