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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
49 program. The server provides a remote login facility
50 with authentication based on privileged port numbers from trusted hosts.
54 .Bl -tag -width indent
56 Set TCP_NODELAY socket option. This improves responsiveness at the expense of
57 some additional network traffic.
59 Ask hostname for verification.
61 Prevent any authentication based on the user's
63 file, unless the user is logging in as the superuser.
65 Disable keep-alive messages.
68 The following options are valid only if Kerberos is in use:
69 .Bl -tag -width indent
71 Enable Kerberos authentication.
77 encryption for all data passed via the rlogin
78 session. This may impact response time
81 utilization, but provides increased security.
86 utility listens for service requests at the port indicated in
89 service specification; see
91 When a service request is received the following protocol
95 The server checks the client's source port.
96 If the port is not in the range 512-1023, the server
97 aborts the connection.
99 The server checks the client's source address
100 and requests the corresponding host name (see
101 .Xr gethostbyaddr 3 ,
105 If the hostname cannot be determined,
106 the dot-notation representation of the host address is used.
107 If the hostname is in the same domain as the server (according to
108 the last two components of the domain name),
112 the addresses for the hostname are requested,
113 verifying that the name and address correspond.
114 Normal authentication is bypassed if the address verification fails.
117 Once the source port and address have been checked,
119 proceeds with the authentication process described in
121 It then allocates a pseudo terminal (see
123 and manipulates file descriptors so that the slave
124 half of the pseudo terminal becomes the
130 The login process is an instance of the
132 program, invoked with the
134 option if authentication has succeeded.
135 If automatic authentication fails, the user is
136 prompted to log in as if on a standard terminal line.
138 The parent of the login process manipulates the master side of
139 the pseudo terminal, operating as an intermediary
140 between the login process and the client instance of the
142 program. In normal operation, the packet protocol described
145 is invoked to provide
147 type facilities and propagate
148 interrupt signals to the remote programs. The login process
149 propagates the client terminal's baud rate and terminal type,
150 as found in the environment variable,
154 The screen or window size of the terminal is requested from the client,
155 and window size changes from the client are propagated to the pseudo terminal.
157 Transport-level keepalive messages are enabled unless the
160 The use of keepalive messages allows sessions to be timed out
161 if the client crashes or becomes unreachable.
163 All initial diagnostic messages are indicated
164 by a leading byte with a value of 1,
165 after which any network connections are closed.
166 If there are no errors before
168 is invoked, a null byte is returned as in indication of success.
173 by the server failed.
185 .Bl -tag -width /etc/hostsxxxxxxxx -compact
187 .It Pa /etc/hosts.equiv
188 .It Ev $HOME Ns Pa /.rhosts
189 .It Pa /var/run/nologin
192 The authentication procedure used here assumes the integrity
193 of each client machine and the connecting medium. This is
194 insecure, but is useful in an
198 A facility to allow all data exchanges to be encrypted should be
201 A more extensible protocol should be used.
208 IPv6 support was added by WIDE/KAME project.