The ZoneAlarm Pro Personal Firewall is a new and improved version of the ZoneAlarm Personal Firewall. ZoneAlarm Pro watches network communications on a per-application basis and asks the user for permission each time an application wants to use the network. The GUI could be a little easier to use and perhaps a little more instructive.
Confusing alerts pop up sometimes.
When the alerts pop up, it does not mention which application caused the alert. ZoneAlarm Pro does have some very good, useful features. There is password protection as well as custom alert and logging. Ports allowed can also be controlled per application. ZoneAlarm Pro also offers mail filtering called MailSafe.