From owner-freebsd-net@FreeBSD.ORG Sun Sep 28 10:15:04 2003 Return-Path: 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 DCEC516A4B3; Sun, 28 Sep 2003 10:15:04 -0700 (PDT) Received: from postfix4-2.free.fr (postfix4-2.free.fr [213.228.0.176]) by mx1.FreeBSD.org (Postfix) with ESMTP id D8DCD4400B; Sun, 28 Sep 2003 10:15:01 -0700 (PDT) (envelope-from yannick.dambielle@free.fr) Received: from shibuya (nord-5-82-67-198-63.fbx.proxad.net [82.67.198.63]) by postfix4-2.free.fr (Postfix) with SMTP id 2BBF5C47B; Sun, 28 Sep 2003 19:15:00 +0200 (CEST) Message-ID: <001401c385e4$0cfde770$3fc64352@shibuya> From: "Dambielle Yannick" To: "Robert Watson" References: Date: Sun, 28 Sep 2003 19:15:00 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 cc: freebsd-net@freebsd.org Subject: Re: tcpdump - tun/tap virtual interfaces X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 28 Sep 2003 17:15:05 -0000 ----- Original Message ----- From: "Robert Watson" To: "Dambielle Yannick" Cc: Sent: Sunday, September 28, 2003 6:40 PM Subject: Re: tcpdump - tun/tap virtual interfaces > > On Sun, 28 Sep 2003, Dambielle Yannick wrote: > > > I've tried to dump some paquets sent to a virtual interface without any > > success for a couple of hours so I ask for some helps to the list. I > > use a FreeBSD 5.0, my kernel has been rebuilt and installed with the > > following option in order to use a tap virtual interface : device tap > > The virtual interface has been created (tap0) and I've attached the IP > > adress 10.0.0.1. It seems ok, I can see it with ifconfig. All the tests > > are local tests. While I ping 10.0.0.1 (paquets are sent and not lost), > > I laught a tcpdump -i tap0 from another shell... Nothing is dumped > > (?!)... Well, if some of you has an idea, I'll be very happy. > > Do you see anything when you ping the broadcast address or other foreign > address of the tap interface? Packets delivered to local IP addresses > generally don't go out an interface. > > Robert N M Watson FreeBSD Core Team, TrustedBSD Projects > robert@fledge.watson.org Network Associates Laboratories > When I try to ping the broadcast address I have the following results: # ping 10.0.0.255 ping: sendto: Permission denied ... Bellow is how I do for setting up a virtual interface : # echo 1 > /dev/tap1 # ifconfig tap1 up # ifconfig tap1 inet 10.0.10.1/24 add # ifconfig <-- show me that tap1 has 10.0.10.1 attached and is also running On the first shell, I ping 10.0.10.1 # ping 10.0.10.1 64 butes from 10.0.10.1: icmp_seq=0 ttl=64 time=0.137ms 64 butes from 10.0.10.1: icmp_seq=0 ttl=64 time=0.137ms ... On a second shell, I try to dump # tcpdump -i tap1 That wait... that wait... Nothing comes :/ Let's try to ping the broadcast address # ping 10.0.10.255 ping: sendto: Permission denied, same as before ... Well, any ideas are welcome.