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32 .\" @(#)rlogind.8 8.1 (Berkeley) 6/4/93
39 .Nd remote login server
43 .Op Fl p Ar portnumber
44 .Op Fl L Ar /bin/login
49 program. The server provides a remote login facility with
50 kerberos-based authentication or traditional pseudo-authentication with
51 privileged port numbers from trusted hosts.
57 No-op. For backwards compatibility. Hostnames are always verified.
59 Prevent any authentication based on the user's
61 file, unless the user is logging in as the superuser.
63 Disable keep-alive messages.
65 Enable kerberos authentication.
67 Do not expect to be spawned by inetd and create a socket and listen on
70 Specifies the port number it should listen on in case the
74 Vacuous, echo "Remote host requires Kerberos authentication" and exit.
76 Provides an encrypted communications channel. This options requires the
80 Specify pathname to an alternative login program.
82 Use the TCP nodelay option (see setsockopt(2)).
85 When a service request is received,
87 verifies the kerberos ticket supplied by the user.
89 For non-kerberised connections, the following protocol is initiated:
92 The server checks the client's source port.
93 If the port is not in the range 512-1023, the server
94 aborts the connection.
96 The server checks the client's source address
97 and requests the corresponding host name (see
102 If the hostname cannot be determined,
103 the dot-notation representation of the host address is used.
104 The addresses for the hostname are requested,
105 verifying that the name and address correspond.
106 Normal authentication is bypassed if the address verification fails.
109 Once the source port and address have been checked,
111 proceeds with the authentication process described in
114 It then allocates a pseudo terminal (see
116 and manipulates file descriptors so that the slave
117 half of the pseudo terminal becomes the
123 The login process is an instance of the
125 program, invoked with the
127 option if authentication has succeeded.
128 If automatic authentication fails, the user is
129 prompted to log in as if on a standard terminal line.
131 The parent of the login process manipulates the master side of
132 the pseudo terminal, operating as an intermediary
133 between the login process and the client instance of the
135 program. In normal operation, the packet protocol described
138 is invoked to provide
140 type facilities and propagate
141 interrupt signals to the remote programs. The login process
142 propagates the client terminal's baud rate and terminal type,
143 as found in the environment variable,
147 The screen or window size of the terminal is requested from the client,
148 and window size changes from the client are propagated to the pseudo terminal.
150 Transport-level keepalive messages are enabled unless the
153 The use of keepalive messages allows sessions to be timed out
154 if the client crashes or becomes unreachable.
156 All initial diagnostic messages are indicated
157 by a leading byte with a value of 1,
158 after which any network connections are closed.
159 If there are no errors before
161 is invoked, a null byte is returned as in indication of success.
166 by the server failed.
173 A more extensible protocol should be used.