SECURITY
Computer security, cybersecurity, or information technology security (IT security) is the protection of computer systems and networks from information disclosure, theft of or damage to your hardware, software, or electronic data, as well as from the disruption or misdirection of the services you provide.
Firewall
A firewall is a security device — computer hardware or software — that can help protect your network by filtering traffic and blocking outsiders from gaining unauthorized access to the private data on your computer.
Inbound firewall rules protect the network against incoming traffic, such as disallowed connections, malware, and denial-of-service (DoS) attacks. Outbound firewall rules protect against outgoing traffic, originating inside a network.
Example: If a database service is hosted on the cloud server, you have to create an inbound firewall rule to allow users to access the port used by the database service and only allow specified IP addresses to access that port.