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

You might also be interested in

Check your security settings

SimpleumCheck Screenshot

SimpleumCheck checks the security settings on your Mac in three stages and gives you recommendations on how you can improve your security even further.

For Free

Protect and encrypt your data

SimpleumSafe Screenshot


Protect your data with SimpleumSafe App for Mac, iPhone and iPad. Don’t compromise when it comes to protecting your data.

Other security setting to check

PLEASE READ THE FOLLOWING TIP AND DISCLAIMER!

Keep in mind: not every security and privacy setting is suitable for everyone. Enhancing the security can lead in losing functionality and/or comfort.
Before making changes, please backup your Mac! Do not make too many change at once. After changing your Mac, check if your normal usage of your Mac has changed in a way which fits to you. Are your really willing to loose some functionality and/or comfort?
Most important is, that you learn and understand what are the advantages and disadvantages of the security settings and that you are aware about the capabilities and risks of your Mac configuration.

To skip this result message from your next security scan, you can deactivate this check. FAQ: How to deactivate a check.

CHECK RESULTS BY SIMPLEUMCHECK DO NOT COVER ALL ASPECTS OF POSSIBLE SECURITY CHECKS OR MAYBE INCORRECT OR INCOMPLETE. THE RESULTS ARE ONLY CLUES FOR RECOMMENDATIONS TO IMPROVE SECURITY AND PRIVACY ON THE MAC.

The use of SimpleumCheck, the checks and FAQ articles are provided under the SimpleumCheck End User License Agreement (EULA).