• the network utility GUI is useful, but you may get the same results via the command line:
$ cd /Applications/Utilities/Network\ Utility.app/Contents/Resources/
$ ./stroke nas-meduz.local 548 550
Port Scanning host: 192.168.0.5

         Open TCP Port:         548             afpovertcp
$ ./stroke shazam.dyndns.org 548 550
Port Scanning host: 82.231.23.196

         Open TCP Port:         548             afpovertcp