Port 3306….TCP
Connection to MySQL/MariaDB databases….
What is Port 3306 for?…
Database. The protocol or service generally associated with this is MySQL / MariaDB….
Transport Protocol
TCP
Safety precautions
Do not publicly expose unless controlled architecture. Use TLS and network filtering…
Should we open this port in the firewall?
Only if a service is actually needed the use it. Apply the principle of any privilege: limit the authorized sources, destinations and interfaces, and then log connections when relevant.
How do I check this port?
Test-NetConnection SERVER -Port 3306
Under Linux, you can use nc -vz SERVER 3306.
Port/service associations are common conventions. An application can be configured on another port.