Messages in this thread |  | | Date | Mon, 16 Sep 2002 13:25:54 -0400 (EDT) | From | Gerhard Mack <> | Subject | Re: Problem: RFC1166 addressing |
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On Mon, 16 Sep 2002 tomc@teamics.com wrote:
> Date: Mon, 16 Sep 2002 11:50:36 -0500 > From: tomc@teamics.com > To: linux-kernel@vger.kernel.org > Subject: Problem: RFC1166 addressing > > RFC 1166 states that: > > > The class A network number 127 is assigned the "loopback" > function, that is, a datagram sent by a higher level protocol > to a network 127 address should loop back inside the host. No > datagram "sent" to a network 127 address should ever appear on > any network anywhere. > > Linux does not enforce this. I have uncovered some users using this > function to attempt to circumvent the firewall. I am able to "create" 127 > network traffic as follows: > > Machine 1: ifconfig eth0:1 127.1.2.3 [ running kernel 2.2.14 ] > > Machine 2: ifconfig eth0:1 127.1.2.4 [ running kernel 2.4.19 ] > > Machine 2: ping 127.1.2.3 > > Packets move between the hosts. Also seems to work on Macintosh.
I would call that a bug in the firewall rules. Depending on the hosts to behave in such a way as to make life easier for the firewall makes for a losing proposition.
Gerhard
-- Gerhard Mack
gmack@innerfire.net
<>< As a computer I find your faith in technology amusing.
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