Learn · Mac
Turn on the Mac firewall
3 min · recommended
· HomeOS can check this for you
Why this matters. A firewall decides which network connections are allowed into your Mac. At home your router already does some of this, but laptops travel to cafés, hotels and airports where anyone on the same Wi-Fi can try to connect. It's off by default on Macs and costs nothing to turn on.
1
Switch it on
Apple menu, then System Settings, then Network, then Firewall. Turn Firewall on.
System Settings › Network › Firewall
Firewall
The firewall is turned on and set up to prevent unauthorized applications, programs, and services from accepting incoming connections.
On
Options…
If an app you trust later asks to accept incoming connections, you can allow it.
Check your understanding
Where does the Mac firewall help most?
On networks you don't control, like cafés, hotels and airports.
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Checked against:
Apple: Block connections to your Mac with a firewall
· last reviewed 2026-09