From owner-freebsd-net Wed Mar 12 12: 9: 8 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 F19F337B401 for ; Wed, 12 Mar 2003 12:09:06 -0800 (PST) Received: from sccrmhc01.attbi.com (sccrmhc01.attbi.com [204.127.202.61]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2509F43FBD for ; Wed, 12 Mar 2003 12:09:06 -0800 (PST) (envelope-from crist.clark@attbi.com) Received: from blossom.cjclark.org (12-234-89-252.client.attbi.com[12.234.89.252]) by sccrmhc01.attbi.com (sccrmhc01) with ESMTP id <2003031220090500100jb2vme>; Wed, 12 Mar 2003 20:09:05 +0000 Received: from blossom.cjclark.org (localhost. [127.0.0.1]) by blossom.cjclark.org (8.12.6/8.12.3) with ESMTP id h2CK93eq016934; Wed, 12 Mar 2003 12:09:03 -0800 (PST) (envelope-from crist.clark@attbi.com) Received: (from cjc@localhost) by blossom.cjclark.org (8.12.6/8.12.6/Submit) id h2CK93RF016933; Wed, 12 Mar 2003 12:09:03 -0800 (PST) X-Authentication-Warning: blossom.cjclark.org: cjc set sender to crist.clark@attbi.com using -f Date: Wed, 12 Mar 2003 12:09:03 -0800 From: "Crist J. Clark" To: Sten Daniel S?rsdal Cc: freebsd-net@FreeBSD.org Subject: Re: Source ip route lookup on incoming packets? Message-ID: <20030312200903.GG16143@blossom.cjclark.org> Reply-To: "Crist J. Clark" References: <0AF1BBDF1218F14E9B4CCE414744E70F07DE63@exchange.wanglobal.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0AF1BBDF1218F14E9B4CCE414744E70F07DE63@exchange.wanglobal.net> User-Agent: Mutt/1.4i 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 Thu, Feb 27, 2003 at 02:02:53PM +0100, Sten Daniel S?rsdal wrote: > > Has anyone made any patches to lookup the source ip for a packet to be routed > so that it comes from the right interface? > I've heard alot of talk from people going to write patches to do this > but no patches have turned up and no help from google. > > What i am looking for is a feature that basically prevents spoofing by looking > the route for the source and match the incoming interface. > A firewall solves the problem but adds alot of administrative overhead and > leaves room for error. > > Is this feature even possible on FreeBSD? For the sake of the email archive (since I know the post's author is already aware of this): Yes this is possible. I just added an option to ipfw(8) to do this. It is called 'verrevpath.' See the thread "Anti-Spoofing Option" on the freebsd-ipfw list. Coming soon to a FreeBSD repository near you. -- 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