From owner-freebsd-net@FreeBSD.ORG Tue May 31 11:07:49 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org 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 6095916A42A for ; Tue, 31 May 2005 11:07:49 +0000 (GMT) (envelope-from french.linuxian@gmail.com) Received: from zproxy.gmail.com (zproxy.gmail.com [64.233.162.193]) by mx1.FreeBSD.org (Postfix) with ESMTP id E379143D1F for ; Tue, 31 May 2005 11:07:48 +0000 (GMT) (envelope-from french.linuxian@gmail.com) Received: by zproxy.gmail.com with SMTP id 12so1826746nzp for ; Tue, 31 May 2005 04:07:48 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=SWnkrFtY31o8WNPO+pjWacwrsFMVxKIjKA3E4CoBPow0w6kmdXlK2kB7Ku0P34F41eIInL2OXHTuawZLrHCV8WKru2lrrMy7ssIgqvQQkDjaEoj3reDfKj1xkPLPQuDKebHu0EGPRT6UJN1lYR3VlBzsHIim4049tASyFO6Dkd8= Received: by 10.36.178.20 with SMTP id a20mr858234nzf; Tue, 31 May 2005 04:07:48 -0700 (PDT) Received: by 10.36.58.12 with HTTP; Tue, 31 May 2005 04:07:48 -0700 (PDT) Message-ID: <3727392705053104072e9547df@mail.gmail.com> Date: Tue, 31 May 2005 07:07:48 -0400 From: Aziz Kezzou To: freebsd-hackers , freebsd-net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Cc: Subject: Routing loop + raw IP packets : looking for clues ... X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Aziz Kezzou List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 May 2005 11:07:49 -0000 Hi all, For the purpose of my project I am simpulating a 3-hop network with QEMU on my workstation, as follows : |---------------------------------| =20 |-------------------------------| =20 |-------------------------------------| |Daemon1(user process)|---tun0---| Daemon 2 on QEMU |---tun1---| Daemon 3 (user porcess) | |---------------------------------| =20 |-------------------------------| =20 |-------------------------------------| My workstation is running FC3 and QEMU is running FreeBSD5.3 I am tryning to exchange raw IP packets between daemon 1 and 3 through daemon 2. I've succeded to by pass the system routing and get packets sent from daemon 1 to daemon 2 and from daemon 2 to daemon 3. BUT, on daemon 3 I can not receive them ??!! However, when I listen with tcpdump on tun0 and tun1 I see the packets travelling as expected : daemon1(192.168.0.1)------>(192.168.0.2)daemon2(192.168.1.2)------> daemon3(192.168.0.2) What could prevent me from receiving packets intended for daemon 3? I am suspecting some hard coded rule to prevent routing loops (which is my case) in the Linux kernel, am I on the right track ? Note : I disabled completely my firewalls, so this could not be the reason. Any help is highly appreciated. -aziz