1 .\" Copyright (c) 1983 The Regents of the University of California.
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms are permitted
5 .\" provided that the above copyright notice and this paragraph are
6 .\" duplicated in all such forms and that any documentation,
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8 .\" distribution and use acknowledge that the software was developed
9 .\" by the University of California, Berkeley. The name of the
10 .\" University may not be used to endorse or promote products derived
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12 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
13 .\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
14 .\" WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16 .\" @(#)rlogind.8 6.8 (Berkeley) 1/6/89
18 .TH RLOGIND 8 "January 6, 1989"
21 rlogind \- remote login server
31 program. The server provides a remote login facility
32 with authentication based on privileged port numbers from trusted hosts.
35 listens for service requests at the port indicated in
36 the ``login'' service specification; see
38 When a service request is received the following protocol
41 The server checks the client's source port.
42 If the port is not in the range 512-1023, the server
43 aborts the connection.
45 The server checks the client's source address
46 and requests the corresponding host name (see
47 .IR gethostbyaddr (3),
51 If the hostname cannot be determined,
52 the dot-notation representation of the host address is used.
54 Once the source port and address have been checked,
56 proceeds with the authentication process described in
58 It then allocates a pseudo terminal (see
60 and manipulates file descriptors so that the slave
61 half of the pseudo terminal becomes the
67 The login process is an instance of the
69 program, invoked with the
71 option if authentication has succeeded.
72 If automatic authentication fails, the user is
73 prompted to log in as if on a standard terminal line. The
75 option prevents any authentication based on the user's
76 ``.rhosts'' file, unless the user is logging in as the superuser.
78 The parent of the login process manipulates the master side of
79 the pseudo terminal, operating as an intermediary
80 between the login process and the client instance of the
82 program. In normal operation, the packet protocol described
85 is invoked to provide ^S/^Q type facilities and propagate
86 interrupt signals to the remote programs. The login process
87 propagates the client terminal's baud rate and terminal type,
88 as found in the environment variable, ``TERM''; see
90 The screen or window size of the terminal is requested from the client,
91 and window size changes from the client are propagated to the pseudo terminal.
93 Transport-level keepalive messages are enabled unless the
96 The use of keepalive messages allows sessions to be timed out
97 if the client crashes or becomes unreachable.
99 All diagnostic messages are returned on the connection
102 after which any network connections are closed.
103 An error is indicated by a leading byte with a value of 1.
109 by the server failed.
113 The user's login shell could not be started.
117 The authentication procedure used here assumes the integrity
118 of each client machine and the connecting medium. This is
119 insecure, but is useful in an ``open'' environment.
121 A facility to allow all data exchanges to be encrypted should be
124 A more extensible protocol should be used.