From owner-freebsd-net Mon Aug 6 6:36: 3 2001 Delivered-To: freebsd-net@freebsd.org Received: from finch-post-12.mail.demon.net (finch-post-12.mail.demon.net [194.217.242.41]) by hub.freebsd.org (Postfix) with ESMTP id B6A0037B41F for ; Mon, 6 Aug 2001 06:35:40 -0700 (PDT) (envelope-from henry@techiebod.com) Received: from [62.49.229.110] (helo=gw1.techiebod.com) by finch-post-12.mail.demon.net with esmtp (Exim 2.12 #1) id 15TkXj-0009Yl-0C for freebsd-net@freebsd.org; Mon, 6 Aug 2001 13:35:39 +0000 Received: by gw1.techiebod.com (zmail, from userid 1000) id D6BDE3E9BBE; Mon, 6 Aug 2001 14:35:38 +0100 (BST) Received: from localhost (localhost [127.0.0.1]) by gw1.techiebod.com (zmail) with ESMTP id D43C13E5E32 for ; Mon, 6 Aug 2001 14:35:38 +0100 (BST) Date: Mon, 6 Aug 2001 14:35:38 +0100 (BST) From: Henry Whincup X-X-Sender: To: "freebsd-net@freebsd.org" Subject: BPF does not pick up loopback activity Message-ID: <20010806140314.O37365-100000@localhost> 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 Take the following example: # ifconfig fxp0 fxp0: flags=8843 mtu 1500 inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255 ether 00:90:27:94:84:34 media: Ethernet autoselect (100baseTX ) status: active # tcpdump -ni fxp0 & # ping 192.168.2.1 PING 192.168.2.1 (192.168.2.1): 56 data bytes 64 bytes from 192.168.2.1: icmp_seq=0 ttl=64 time=0.059 ms 64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=0.057 ms ^C --- 192.168.2.1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.057/0.058/0.059/0.001 ms # ping 192.168.2.2 PING 192.168.2.2 (192.168.2.2): 56 data bytes 64 bytes from 192.168.2.2: icmp_seq=0 ttl=255 time=3.134 ms 14:33:23.291728 arp who-has 192.168.2.2 tell 192.168.2.1 14:33:23.293210 arp reply 192.168.2.2 is-at 0:d0:ba:a:91:c0 14:33:23.293227 192.168.2.1 > 192.168.2.2: icmp: echo request 14:33:23.294782 192.168.2.2 > 192.168.2.1: icmp: echo reply 64 bytes from 192.168.2.2: icmp_seq=1 ttl=255 time=1.408 ms 14:33:24.297997 192.168.2.1 > 192.168.2.2: icmp: echo request 14:33:24.299352 192.168.2.2 > 192.168.2.1: icmp: echo reply ^C --- 192.168.2.2 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 1.408/2.271/3.134/0.863 ms # Note that the packets sent to the local IP address are not picked up by tcpdump. This can be tried with any traffic type, I have just used ping as an example. Is this the correct/desired behaviour? If it is, is there any other way to capture these packets? Thanks Henry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message