Windows XP SP2 (Home Edition)
Windows Firewall
McAffee Personal Firewall Plus (Tight Security Setting)
This happens when I try to test my firewall's vulnerabilitys through McAffee:

"Unable to Probe
The IP address requesting this page is different from the IP address of your computer. This indicates that your computer is behind a proxy or NAT. These devices allow you to access the Internet by relaying traffic, typically from multiple computers, through a single IP address.
We are unable to directly probe your computer, you should take comfort from this. You have that much more protection between your computer and the Internet."

I have a 576Kbps DSL modem (BT Voyager 105 USB) and connect to the internet through another computer on my network (via 100MB LAN), the server PC runs Windows Firewall and McAffee (Tight Security)

I have a Mentor 5 port 10/100Mbps Ethernet Switch, which links our 3 PCs.

I'm at home.
Hope there isnt too much worthless info here.
Cheers, Rob