Firewall security in macOS
macOS includes a built-in firewall to protect the Mac from
network access and denial-of-service attacks. It can be
configured in the Security & Privacy pane of System
and supports the following configurations:
o Lock all incoming connections, regardless of app.
o Automatically allow built-in software to receive incoming
o Automatically allow downloaded and signed software to
receive incoming connections.
o Add or deny access based on user-specified apps.
o Prevent the Mac from responding to ICMP (Internet Control
Message Protocol) probing and portscan requests.
Turn On Firewall
Change Firewall settings on Mac
Block connections to your Mac with a firewall
Apple Platform Security