Firewall rules
Firewall rules are a set of conditions used to test all network connections and determine the appropriate actions for these conditions. Using firewall rules, you can define the type of action to take when a connection defined by the rule is established.
Incoming connections are initiated by a remote computer attempting to establish a connection with the local system. Outgoing connections work in the opposite way–the local system contacts a remote computer.
If a new unknown communication is detected, you must carefully consider whether to allow or deny it. Unsolicited, unsecured, or unknown connections pose a security risk to the system. If such a connection is established, ESET recommends that you pay particular attention to the remote computer and the application trying to connect to your computer. Many infiltrations try to obtain and send private data, or download other malicious applications to host workstations. The firewall enables you to detect and terminate such connections.
By default, applications signed by Apple can automatically access the network. If you want to disable this capability, deselect Allow software signed by Apple to access the network automatically.