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28 .\" @(#)rlogind.8 8.1 (Berkeley) 6/4/93
36 .Nd remote login server
43 utility is the server for the
46 The server provides a remote login facility
47 with authentication based on privileged port numbers from trusted hosts.
51 .Bl -tag -width indent
53 Set TCP_NODELAY socket option.
54 This improves responsiveness at the expense of
55 some additional network traffic.
57 Ask hostname for verification.
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.
68 utility listens for service requests at the port indicated in
71 service specification; see
73 When a service request is received the following protocol
77 The server checks the client's source port.
78 If the port is not in the range 512-1023, the server
79 aborts the connection.
81 The server checks the client's source address
82 and requests the corresponding host name (see
87 If the hostname cannot be determined,
88 the dot-notation representation of the host address is used.
89 If the hostname is in the same domain as the server (according to
90 the last two components of the domain name),
94 the addresses for the hostname are requested,
95 verifying that the name and address correspond.
96 Normal authentication is bypassed if the address verification fails.
99 Once the source port and address have been checked,
101 proceeds with the authentication process described in
103 It then allocates a pseudo terminal (see
105 and manipulates file descriptors so that the slave
106 half of the pseudo terminal becomes the
112 The login process is an instance of the
114 program, invoked with the
116 option if authentication has succeeded.
117 If automatic authentication fails, the user is
118 prompted to log in as if on a standard terminal line.
120 The parent of the login process manipulates the master side of
121 the pseudo terminal, operating as an intermediary
122 between the login process and the client instance of the
125 In normal operation, the packet protocol described
128 is invoked to provide
130 type facilities and propagate
131 interrupt signals to the remote programs.
133 propagates the client terminal's baud rate and terminal type,
134 as found in the environment variable,
138 The screen or window size of the terminal is requested from the client,
139 and window size changes from the client are propagated to the pseudo terminal.
141 Transport-level keepalive messages are enabled unless the
144 The use of keepalive messages allows sessions to be timed out
145 if the client crashes or becomes unreachable.
147 .Bl -tag -width /etc/hostsxxxxxxxx -compact
149 .It Pa /etc/hosts.equiv
150 .It Ev $HOME Ns Pa /.rhosts
151 .It Pa /var/run/nologin
154 All initial diagnostic messages are indicated
155 by a leading byte with a value of 1,
156 after which any network connections are closed.
157 If there are no errors before
159 is invoked, a null byte is returned as in indication of success.
164 by the server failed.
181 IPv6 support was added by WIDE/KAME project.
183 The authentication procedure used here assumes the integrity
184 of each client machine and the connecting medium.
186 insecure, but is useful in an
190 A facility to allow all data exchanges to be encrypted should be
193 A more extensible protocol should be used.