[ILUG] Firewalls... linux -v- BSD

[dude ilug]

Thanks for all the replies and tangent discussion.

I'm not going to touch the Router/ADSL2 modem, magnet won't allow and
even though I could possibly get access anyway, I might disturb the
VOIP(?) for the phone or other requirements. So, the options entailing
changing the router settings are out.
[i.e. to set the router in bridging mode, and use a firewall just
inside it, doing the Routing and a DHCP Relay, and whether or not it
would need to be doing any PPPoE that may be there (think not from the
posts) ]

Anyway, if I'm getting external IP's I assume the router may already
be in a bridging mode or at least doing some DHCP relaying.

What I will try is the internal bridging firewall with etables.
I read a little on this and it looks handy enough, could be easier if
there is a packaged linux distro set up for just this with some sort
of gui manager or something but I guess I'll be learning iptables.

I have one question on this, that machine will have no ip addresses in
use aiui, so,  will I be able to set it up somehow to check the net
for automatic updates for e.g. ?
Or will it be just the old box in the middle passing packets around
based on my rules and with no access to other machines itself ?
If so, I wonder could I use a 3rd (or 4th if i add a nic for a WAN)
nic for this, or might that interfere with the rest of the machine and
it's main task as firewall/router.


I am also interested in the similiar but different (aiui) setup of the
2-nic machine between the router and lan, with a DHCP Relay and
Firewall software. However, considering I'm not going to be using any
internal network addresses, just dynamic 'public' ips, would this
really work ?
I guess I just can't imagine what ips would be on each of the networks
i/fs, who would assign them and how to be sure they wouldn't cause
problems?
Will have to read further on this one.
Pointers appreciated.

Thanks again, if i get it working i'll report back.