LeakTest is a safe and small (27k bytes), completely benign chameleon utility which can be used to simulate the presence and effect of Trojan horses, viruses, and adware/spyware running in your computer. It simply and quickly tells you whether it has been able to slip out past your firewall's outbound Trojan/Virus/Spyware protections and establish a standard TCP connection with our NanoProbe server.

LeakTest can also operate in stealth mode by holding down either Shift key when testing, or adding the word stealth to the command line, to render it further invisible to some firewalls.

LeakTest is non-expiring freeware written by Steve Gibson, in order to empower you with the ability to test your own outbound Internet firewall defenses.