Activate your firewall: Mac OS 10.7 (Lion)

A firewall protects your computer from Internet worms that exploit open ports and operating system vulnerabilities. Follow these instructions to activate the firewall on your Mac OS 10.7 (Lion) computer.


You should activate only ONE firewall on your computer.

  1. From the Apple menu, click System Preferences.
  2. In the System Preferences window, click the Security & Privacy icon in the top row.
  3. In the Security & Privacy window, click the Firewall tab.
  4. If not already enabled, click Start to turn on the firewall.
  5. Close the Security & Privacy window.