rcp—
A remote file transfer utility.
rexec—
A remote command-execution utility.
rlogin—
A remote login utility.
rsh—
A remote command-execution utility.
ruptime—
A utility that displays system information on uptime and the number of connected users.
rwho—
A utility that displays information on currently connected users.
Telnet—
A remote terminal utility.
trusted access—
A weak security system in which a system administrator designates remote hosts and users who are trusted to access the local system.