MATE's Firewall Configuration utility (Gufw), found in the Control Center
at Menu > Control Center > Firewall Configuration, provides an uncomplicated way
to manage your firewall settings. The firewall is not enabled by default in MATE because by default, MATE does not open ports to
the outside world. If you do choose to enable the firewall, and if you are a normal user, you will be safe with these
settings:
Status=On
Incoming=Deny
Outgoing=Allow
No need to set the firewall to autostart. After you change the settings they will remain in place until you change them again.