JFirewallTest is a free Java Webstart application that tests for holes or open ports in your firewall. Unlike other solutions, JFirewallTest is a two stage testing procedure that tests all 65,536 ports very rapidly. After testing is complete, JFirewallTest will present a page of results reporting exactly what ports are open and accessible to others on the Internet. The list includes information about common services associated with each port and an estimate of the vulnerability.