Here are my OS X Firewall settings. See also: Mac OS Settings, Operating Systems, Software.
Firewall Options
(Applications)
x means "Allow incoming connections", otherwise it's "Block incoming connections".
[x] Adium.app
[x] Android Studio.app
[x] FaceTime.app
[ ] Final Cut Pro.app
[ ] Finder.app
[ ] gamed (Game Center) (user-facing Game Center app is no longer available since MacOS 10.12 Sierra, it wasn't used much)
[x] Spotify.app
[x] Steam.app
[ ] Unity.app
[ ] VLC.app
[ ] Automatically allow signed software to receive incoming connections
[x] Enable stealth mode ("Don't respond to or acknowledge attempts to access this computer from the network by test applications using ICMP, such as Ping.")
When you press the "[+]" button to add an application, you will be taken to "Macintosh HD, Applications" directory.
The "Macintosh HD, Applications" is not the only place where there are applications. See also "Users, USER, Applications".
Adding an application with the "[+]" button may not be sufficient as I noticed with Steam and with video games using TCP and/or UDP. You still need to answer to the following question:
Do you want the application "NAME.app" to accept incoming network connections?
Clicking Deny may limit the application's behavior. This setting can be changed in the Firewall pane of Security & Privacy preferences.
man pfctl
sudo pfctl -vnf /etc/pf.conf
Last modified: August 23rd, 2018
Author: Tomi Häsä (tomi.hasa@gmail.com)
URL: http://sites.google.com/site/tomihasa/os-x-firewall-settings