Firewall: Accept or deny requests depending on IP address

This class can be used to accept or deny requests depending on the user machine IP address.

It can look at the current user IP address and decide to accept or deny the request depending on rules defined in a separate rules file. It can also detect IP addresses behind proxies.

The rules define whether to accept or deny requests from individual IP addresses or whole ranges.

When the current user IP address is denied, it can either redirect the user to another page using Javascript, show a given message, or issue a denied access response header.