Test whether outbound port is open on Mac OS X 10.9, 10.8, 10.7

Wondering if a certain outbound port on your Mac is open or closed? Here’s a way to test if that port is open using netcat via the command line in terminal, using a free service from portquiz.net:

From terminal, enter:

where 443 is the port number you want to test.

Control-c will kill net cat after you get the info you want.