There are times when you'll need to block certain ranges of IP addresses (or known hosts) based on a service and/or block specific IP addresses from gaining access to your network (or machine).
Peer Guardian 2 makes this task simple in a Windows (currently 98/ME/2000/XP) environment.
this can be turned off via the config file Allow Updates setting, but is not recommended!
Peer Guardian 2 is Phoenix Labs' premier IP blocker for Windows.
Peer Guardian 2 integrates support for multiple lists, list editing, automatic updates, and blocking all of IPv4 (TCP, UDP, ICMP, etc), making it the safest and easiest way to protect your privacy on P2P.
The standard installation steps will take place and, once the application is installed, you will be asked to walk through some initial setup configurations.
The first part of the setup will ask what types of lists to install.
The application is open source, so you can download the source code, modify it, and even create your own branch of the software.