It's one of these that leak-tests firewalls. There was another site that you could use by yourself but it's unvailable atm due to monthly fee ( www.firewallleaktester.com )
My Computer
OS
Win 7 RC 64bit b7229
CPU
Intel Core 2 DUO E8400 3,0Ghz 6Mb STEP E0
Motherboard
ASUS P5Q-E
Memory
TEAM GROUP ELITE DDR2 800 PC8500 (5-5-5-15) 2*2GB
Graphics Card(s)
Club3D ATI HD4850 Acrtic Cooling Ed. 512Mb 256Bit GDDR-3