From owner-freebsd-questions Fri Jun 23 3:32:49 2000 Delivered-To: freebsd-questions@freebsd.org Received: from mail.hellasnet.gr (mail.hellasnet.gr [212.54.192.3]) by hub.freebsd.org (Postfix) with ESMTP id 501D237B90C for ; Fri, 23 Jun 2000 03:32:36 -0700 (PDT) (envelope-from keramida@ceid.upatras.gr) Received: from hades.hell.gr (ppp4.patr.hellasnet.gr [212.54.197.19]) by mail.hellasnet.gr (8.9.1/8.9.1) with ESMTP id MAA18489; Fri, 23 Jun 2000 12:31:33 +0200 (GMT) Received: (from charon@localhost) by hades.hell.gr (8.10.2/8.10.2) id e5MLfjl17357; Fri, 23 Jun 2000 00:41:45 +0300 (EEST) Date: Fri, 23 Jun 2000 00:41:45 +0300 From: Giorgos Keramidas To: cjclark@alum.mit.edu Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Confused by Loopback Message-ID: <20000623004145.B17268@hades.hell.gr> References: <20000621205221.A43715@pool0586.cvx20-bradley.dialup.e> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <20000621205221.A43715@pool0586.cvx20-bradley.dialup.e>; from cristjc@earthlink.net on Wed, Jun 21, 2000 at 08:52:21PM -0700 X-PGP-Fingerprint: 3A 75 52 EB F1 58 56 0D - C5 B8 21 B6 1B 5E 4A C2 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > $ netstat -rn > Routing tables > > Internet: > Destination Gateway Flags Refs Use Netif Expire > default 207.217.148.27 UGSc 11 22 tun0 > 127.0.0.1 127.0.0.1 UH 0 0 lo0 > 207.217.148.27 209.179.254.29 UH 12 0 tun0 While not connected to the network, I can see in my machine: % netstat -rn Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire 127.0.0.1 127.0.0.1 UH 1 11250 lo0 > Notice there is no LAN entry for the 127-net like the ifconfig(8) mask > says. So if I were to do something silly like, > > $ ping 127.0.0.2 > > It goes out over the tun0 interface. I noticed this because for some > perverse reason I tried, > > $ ping 127.255.255.255 > > And started getting replies from other hosts! I tried a traceroute(8) > and watched 127.0.0.2 packets make their happy way out towards the > I'net. > > Tell me I'm missing something silly here. You have not missed anything. That is exactly the way it works. Why does it puzzle you? Because a network route for 127.0.0.0/8 does not exist in your routing table by default? If what puzzles you is that you actually *got* some replies back, you have to use a firewall to stop packets originating from, or destined to hosts in 127.0.0.0/8, from traversing your tun0 interface :) -- Giorgos Keramidas, < keramida @ ceid . upatras . gr > For my public key: finger keramida@ceid.upatras.gr To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message