← Basic Checks

Basic · Check result

Turn on the built-in firewall on Mac

Turn on the built-in macOS firewall to reduce unwanted incoming connections from the internet or another network. It is an application firewall: you can allow or block incoming access for specific apps and services.

macOS 13 and later

  1. Choose Apple menu > System Settings.
  2. Click Network in the sidebar.
  3. Click Firewall, then turn it on.
  4. Click Options to review allowed and blocked apps, automatic allowances, Block all incoming connections, and stealth mode.
Network settings showing the macOS Firewall switch

macOS 10.11 through 12

  1. Choose Apple menu > System Preferences > Security & Privacy.
  2. Open Firewall and unlock the preference pane.
  3. Click Turn On Firewall.
  4. Open Firewall Options to review application rules.
Legacy Security & Privacy pane showing Firewall turned on

Security and functional limits

  • The firewall controls incoming connections. It does not normally tell you which remote services an app contacts or block outgoing traffic.
  • It does not replace software updates, malware protection built into macOS, strong authentication, or a network router’s firewall.
  • Sharing services can create allowed incoming paths. Turn off services such as File Sharing when they are not needed.
  • Blocking an app can interfere with that app or dependent software. Review prompts and rules instead of denying them without context.

Then review whether to automatically allow signed software and whether stealth mode fits your network.

Primary sources