Subject: Re: multiple IP addresses over one PPPoE connection
To: Alicia da Conceicao <alicia@engine.ca>
From: Martin Husemann <martin@duskware.de>
List: tech-net
Date: 06/06/2007 20:48:09
On Wed, Jun 06, 2007 at 01:05:51PM -0400, Alicia da Conceicao wrote:
> Could I set up a pseudo bridge interface between the pppoe0 and fxp1
> (sDSL & DMZ) interfaces?  Is there a better way to do this?  I am
> running NetBSD 3.1 (i386) on the router.

There are several ways to do that. I guess the most simple is to just use you
routers public address both on pppoe0 and fxp0, turn on ip forwarding and set
apropriate netmasks, and double check routes (especially the default route,
so it goes out of pppoe0).

I have a similar setup, where I (mostly for historical reasons combined with
administrative laziness) use NAT to do it: the internal network interface has
a 192.168.x.x number, all public servers too, and I map those internal
numbers via NAT on the router to the public address. This made filtering
rules pretty easy in my case, but I'm not sure I would choose this aproach
again for a from-scratch setup, especially if IPv6 would be involved and
NAT could be avoided (in my current setup I need NAT for other reasons
anyway).

Martin