Internet-Security.com TCP port 992 details

TCP port 992 is the IANA-registered port for “telnets” (Telnet over TLS/SSL).
IBM z/OS Communications Server’s TN3270E Telnet server commonly offers secure TN3270/Telnet on 992; clients like x3270/wx3270, Rocket BlueZone, and IBM Personal Communications connect to it with TLS.
IBM i (AS/400) systems provide SSL/TLS-protected 5250 terminal access on 992 via the built-in Telnet server; clients such as IBM i Access Client Solutions, tn5250j, and Mocha TN5250 use this port.
Linux/Unix systems can run the telnet-ssl/telnetd-ssl packages (e.g., on Debian/Ubuntu), which implement Telnet over TLS and listen on 992 by default.
IBM z/VM installations also expose secure Telnet services for 3270 terminals on 992 when configured with TLS.
Security note: attackers do scan port 992 for exposed “telnets” services to attempt credential brute-force or exploit outdated Telnet/TLS stacks, so it’s often recommended to use SSH instead if possible.

TCP 992