What port does RDP (Remote Desktop Protocol) use, and what two security risks exist when exposing RDP directly to the internet?

• A.RDP uses TCP 3389. Security risks: (1) Brute-force and credential stuffing attacks: RDP on the internet is continuously targeted by automated scanners; without account lockout and strong passwords, attackers can try millions of credentials. (2) RDP vulnerabilities: historically critical CVEs (BlueKeep CVE-2019-0708, DejaBlue CVE-2019-1182) allow unauthenticated remote code execution on exposed RDP services. Mitigation: never expose 3389 directly; use VPN or RD Gateway, enable Network Level Authentication (NLA), and use strong credentials
• B.RDP uses TCP 3389. The only security risk is session hijacking; brute-force attacks do not work because RDP has built-in lockout that cannot be bypassed; additionally, full-duplex links halve throughput because both directions share one collision timer. SFTP is FTP wrapped in SSL, listening on TCP 990 alongside implicit FTPS. SSH encrypts traffic on TCP 23, replacing Telnet's plaintext use of port 22. MPLS labels are assigned by the customer's DHCP server at each site. H.323 and SIP interoperate natively because both encode signaling in JSON