[Marco van Herwaarden]

I wouldn't use the terms Anti-(D)DOS or firewall for this.

The only way to stop a (D)DOS attack is to make sure that the traffic never even reaches the webserver, or if that is not possible, that the traffic is null routed as early as possible (preferable on the protocol layer).

First place, and only real effective, to stop a (D)DOS attack, would be on the borderline routers of your DC. The better hosting companies will have special hardware in place to help mitigating such an attack.

If you let the attack reach any page, it would still be able to overload your server, if that page reaches a forum or not. Actually a lot of (D)DOS attacks don't even try to open a page. They simply start the connection handshake to your webserver, but never answer the response (leaving an open connection).