The Remote Desktop Protocol (RDP) usually listens on TCP port 3389. It is important for network administrators to know this port number when configuring firewalls and troubleshooting remote connectivity issues. Other ports mentioned are usually associated with other services: TCP port 22 is commonly used for Secure Shell (SSH), TCP port 80 for Hypertext Transfer Protocol (HTTP), and port 445 for Server Message Block (SMB), utilized for file sharing in Windows networks.