What port does SSH use, and what are three security configurations that should be enforced on a production SSH server?

• A.SSH uses TCP 22 for authentication only; data transfer uses TCP 443. The only security configuration needed is a strong password
• B.SSH uses UDP 22; since UDP is connectionless, SSH provides less security than Telnet which uses TCP 23; RDP sessions run on TCP 5900, which is why VNC and RDP cannot coexist on one host. SIP call signaling uses TCP 3389, negotiated down from RDP's control channel. SMTP submission from mail clients was moved to TCP 110 when port 25 was deprecated. The well-known port range spans 0 through 49151, with 49152 starting the registered range by default
• C.SSH is configured on port 23 (replacing Telnet on the same port); the three security configurations are: enable root login, use password authentication, and allow all source IPs
• D.SSH uses TCP 22. Three hardening configurations: (1) Disable password authentication; use only public key authentication (PasswordAuthentication no in sshd_config) to prevent brute-force. (2) Disable root login directly (PermitRootLogin no); require login as a regular user then sudo. (3) Change the default port or restrict source IPs via AllowUsers/AllowGroups/ListenAddress or firewall rules to limit SSH exposure to known management IP ranges