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32 .\" @(#)rlogind.8 8.1 (Berkeley) 6/4/93
40 .Nd remote login server
47 utility is the server for the
50 The server provides a remote login facility
51 with authentication based on privileged port numbers from trusted hosts.
55 .Bl -tag -width indent
57 Set TCP_NODELAY socket option.
58 This improves responsiveness at the expense of
59 some additional network traffic.
61 Ask hostname for verification.
63 Prevent any authentication based on the user's
65 file, unless the user is logging in as the superuser.
67 Disable keep-alive messages.
72 utility listens for service requests at the port indicated in
75 service specification; see
77 When a service request is received the following protocol
81 The server checks the client's source port.
82 If the port is not in the range 512-1023, the server
83 aborts the connection.
85 The server checks the client's source address
86 and requests the corresponding host name (see
91 If the hostname cannot be determined,
92 the dot-notation representation of the host address is used.
93 If the hostname is in the same domain as the server (according to
94 the last two components of the domain name),
98 the addresses for the hostname are requested,
99 verifying that the name and address correspond.
100 Normal authentication is bypassed if the address verification fails.
103 Once the source port and address have been checked,
105 proceeds with the authentication process described in
107 It then allocates a pseudo terminal (see
109 and manipulates file descriptors so that the slave
110 half of the pseudo terminal becomes the
116 The login process is an instance of the
118 program, invoked with the
120 option if authentication has succeeded.
121 If automatic authentication fails, the user is
122 prompted to log in as if on a standard terminal line.
124 The parent of the login process manipulates the master side of
125 the pseudo terminal, operating as an intermediary
126 between the login process and the client instance of the
129 In normal operation, the packet protocol described
132 is invoked to provide
134 type facilities and propagate
135 interrupt signals to the remote programs.
137 propagates the client terminal's baud rate and terminal type,
138 as found in the environment variable,
142 The screen or window size of the terminal is requested from the client,
143 and window size changes from the client are propagated to the pseudo terminal.
145 Transport-level keepalive messages are enabled unless the
148 The use of keepalive messages allows sessions to be timed out
149 if the client crashes or becomes unreachable.
151 .Bl -tag -width /etc/hostsxxxxxxxx -compact
153 .It Pa /etc/hosts.equiv
154 .It Ev $HOME Ns Pa /.rhosts
155 .It Pa /var/run/nologin
158 All initial diagnostic messages are indicated
159 by a leading byte with a value of 1,
160 after which any network connections are closed.
161 If there are no errors before
163 is invoked, a null byte is returned as in indication of success.
168 by the server failed.
185 IPv6 support was added by WIDE/KAME project.
187 The authentication procedure used here assumes the integrity
188 of each client machine and the connecting medium.
190 insecure, but is useful in an
194 A facility to allow all data exchanges to be encrypted should be
197 A more extensible protocol should be used.