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. 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
• B.SSH uses UDP 22; since UDP is connectionless, SSH provides less security than Telnet which uses TCP 23
• 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