The server provides a remote login facility with authentication based on privileged port num- bers from trusted hosts. Ask hostname for verification. Disable keep-alive messages. The server checks the client's source port. If the port is not in the range 512-1023, the server aborts the connection.
Normal authentication is bypassed if the address verifica- tion fails.
If automatic authentication fails, the user is prompted to log in as if on a standard terminal line. The parent of the login process manipulates the master side of the pseudo terminal, operating as an intermediary between the login process and the client instance of the rlogin program. The screen or window size of the terminal is requested from the client, and window size changes from the client are propagated to the pseudo terminal. The authentication procedure used here assumes the integrity of each client machine and the connecting medium. A facility to allow all data exchanges to be encrypted should be present.