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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.
70 The following options are valid only if Kerberos is in use:
71 .Bl -tag -width indent
73 Enable Kerberos authentication.
79 encryption for all data passed via the rlogin
81 This may impact response time
84 utilization, but provides increased security.
89 utility listens for service requests at the port indicated in
92 service specification; see
94 When a service request is received the following protocol
98 The server checks the client's source port.
99 If the port is not in the range 512-1023, the server
100 aborts the connection.
102 The server checks the client's source address
103 and requests the corresponding host name (see
104 .Xr gethostbyaddr 3 ,
108 If the hostname cannot be determined,
109 the dot-notation representation of the host address is used.
110 If the hostname is in the same domain as the server (according to
111 the last two components of the domain name),
115 the addresses for the hostname are requested,
116 verifying that the name and address correspond.
117 Normal authentication is bypassed if the address verification fails.
120 Once the source port and address have been checked,
122 proceeds with the authentication process described in
124 It then allocates a pseudo terminal (see
126 and manipulates file descriptors so that the slave
127 half of the pseudo terminal becomes the
133 The login process is an instance of the
135 program, invoked with the
137 option if authentication has succeeded.
138 If automatic authentication fails, the user is
139 prompted to log in as if on a standard terminal line.
141 The parent of the login process manipulates the master side of
142 the pseudo terminal, operating as an intermediary
143 between the login process and the client instance of the
146 In normal operation, the packet protocol described
149 is invoked to provide
151 type facilities and propagate
152 interrupt signals to the remote programs.
154 propagates the client terminal's baud rate and terminal type,
155 as found in the environment variable,
159 The screen or window size of the terminal is requested from the client,
160 and window size changes from the client are propagated to the pseudo terminal.
162 Transport-level keepalive messages are enabled unless the
165 The use of keepalive messages allows sessions to be timed out
166 if the client crashes or becomes unreachable.
168 All initial diagnostic messages are indicated
169 by a leading byte with a value of 1,
170 after which any network connections are closed.
171 If there are no errors before
173 is invoked, a null byte is returned as in indication of success.
178 by the server failed.
190 .Bl -tag -width /etc/hostsxxxxxxxx -compact
192 .It Pa /etc/hosts.equiv
193 .It Ev $HOME Ns Pa /.rhosts
194 .It Pa /var/run/nologin
197 The authentication procedure used here assumes the integrity
198 of each client machine and the connecting medium.
200 insecure, but is useful in an
204 A facility to allow all data exchanges to be encrypted should be
207 A more extensible protocol should be used.
214 IPv6 support was added by WIDE/KAME project.