Opening OS X's Firewall for your Server

Open the Firewall on your Mac

To check the OS X firewall, open System Preference's Sharing Preference pane, and visit the Firewall tab. If you have never turned the firewall on, it's an excellent idea (especially since you are about to expose your home network to the big bad internet.) If you have turned on a service already known to OS X, you should see that the OS X firewall (if it is running) has already added that server's port to the Allow List.

Firewall Preferences

If you want to use a server that isn't a standard OS X service, you'll need to customize your OS X firewall setup with the port(s) that service uses. You do that by clicking the New button, then selecting Other from the "Port Name" pull-down, and filling in the port number (or range of port numbers) and a description. For example:

Firewall Custom Entry

Then, locate your new entry in the "Allow" list and check it to open the port(s).

Here's a list of some of the more common ports:

PortService
3283Apple Remote Desktop
6346Gnutella file sharing
6881-6889BitTorrent file sharing

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