quote:
How do you cloak or forge a legit ip address while keeping the proticols in check so that people can still access the site?
Are you serious? Heh...
With $500, you can easily buy a cheapo 'puter for $300, router for $100 (hell, even less), and assorted things (NIC, etc. etc.) with the rest of the money (and have enough left for several pizzas). Assuming you're not planning on getting lots of traffic, it should easily keep up with everything (your main bottleneck will be your bandwidth).
Look up Apache, MySQL (if you're planning on having a databsae-driven forum), and take a look at a service along the lines of no-ip.com. Security and what not is a pretty large topic, but what you're looking for should be extensively covered on the net.
Also, one last question: why not just pay for webhosting? You can get mighty decent hosting for $10/month, plus $10/year for a domain.