Personal Firewall supports third-party extentions.

Extentions are intended to add extra features to the program.

Once added, Firewall remembers extention's MD5 checksum. Later, before loading extention, program will compare its checksum and load it automatically if checksum is correct.

Extention will not be loaded, and you will see a warning message in the Log, if extention is ever changed, or replaced with another one.