Configure an Application Layer Firewall setting in Apple Business Essentials
The Application Layer Firewall setting is used to turn on the firewall in macOS to prevent unwanted connections from the internet or other networks.
A Mac can still allow access through the firewall for some services and apps. For example:
If you turn on a sharing service, such as file sharing, macOS opens a specific port for the service to communicate through.
An app or service on another system can request and be given access through the firewall, or it might have a trusted certificate and therefore be allowed access.
In Apple Business Essentials, sign in with a user that has the role of Administrator.
Select Settings
in the sidebar, then select All Settings.This setting is available only for macOS.
Select the Add button
next to Application Layer Firewall 
, then do one or both of the following:Block all incoming connections: This option blocks all incoming connections except those required for basic network and internet services, such as DHCP, Bonjour, and IPsec. This also prevents connections to all other sharing services.
Turn on Stealth mode: This option prevents a Mac from responding to probing requests that can be used to reveal its existence. The Mac still answers requests from authorized apps, but unauthorized requests such as ICMP (ping) get no response.
Select Save.