On an Intel desktop Mac, I want to stop a video game from accessing the local network without disrupting any other networking for other software or system programs. I looked through the firewall options in System Prefs, but I didn't see a way to stop just that program from communicating with the network. I then tried to change the port number for networking within the game itself. It didn't seem to work. Basically I want the game to still work on that machine, just not be able to see or communicate with other games on the local area network. I'm trying to stop my disruptive coworker from playing networked Halo on his Intel Mac with other coworkers.
How can I block a specific Mac program from accessing the local network?
Little Snitch is a pretty good utility for preventing specific apps from getting network access, and lets you set specific rules to allow or block addresses, ports and protocols. I've linked below to the website for it. Little snitch has a 3-hour-at-a-time demo mode, and costs $30 for one license with multiple licenses getting a discount. Hope that helps!
