TELNET

TELNET allows users terminal access to a system over a TCP/IP network. TELNET runs under both native MVS and USS.

If running under native MVS:

Users are forced to log on to TELNET itself if the TELNET configuration statements in the TCP/IP profile data set do not specify a DFLTAPPL. If configured this way users require the TCP/IP facility.
Users logon to a session manager such as CA‑TPX™ if DFLTAPPL is specified. The session manager then controls access through its security interface.