Network ports are numbers from 0 to 65535 that tell a device which service a connection is meant for, such as 443 for HTTPS (encrypted web traffic) or 3389 for RDP (Remote Desktop Protocol). They are used by TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). Every open port exposes a service, so unused ports should be closed.
How TecnetOne handles it: Vulnerability Assessment
TCP and UDP ports, open ports, common ports, port number, well-known ports