[SWLUG] Networking without Smoothwall

Justin Mitchell justin at discordia.org.uk
Mon May 15 08:23:48 UTC 2006

On Mon, 2006-05-15 at 01:04 +0100, Stephanos wrote:
> Dear All
> Currently, I have an NTL broadband modem which connects to a Smoothwall 
> box and then onto a switch.  From this switch comes three nodes.  All 
> work OK.
> I am thinking of removing the Smoothwall box, in order to experiement 
> with software firewalls, but I am not sure that the modem can be 
> connected to the switch direct.

The NTL connection only allows for one registered MAC address and one IP
address (* unless they changed the rules when i wasnt looking)

You have to have a box which will not only route for you, but also
masquerade (aka NAT), and will thus make your network of three computers
look like a single one to the outside world.

your smoothwall box is therefore most likely to be dealing with giving
out private ip addresses to your inside nodes, routing that traffic and
translating it to/from the single public ip address that ntl gives you.
not to mention all the firewalling stuff that it adds too.

if you connected your switch direct to the cable modem then only one of
the computers would be able to get a dhcp lease, and thus ip address,
and be the only computer able to talk to the internet.   afair you had
to use an ntl website to register your mac address, so switching which
computer will get the internet access would be pretty tedious also.

if you wanted to remove the smoothwall box simply because it is
cumbersome or failing, then you can buy a small cheap 'broadband router'
box pretty easily for about 30 or 40 quid, it will be a box that looks
pretty much like a normal small hub/switch but has an additional 'wan'
ethernet port, inside its a router/firewall/nat/dhcp/etc device, just
typically with less features than smoothwall gave you.

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