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Power 6/32 Unix version 1.21

.TH RLOGIND 8C "4 March 1983"
.UC 4
.SH NAME
rlogind \- remote login server
.SH SYNOPSIS
.B /etc/rlogind
[
.B \-d
]
.SH DESCRIPTION
.I Rlogind
is the server for the 
.IR rlogin (1C)
program.  The server provides a remote login facility
with authentication based on privileged port numbers.
.PP
.I Rlogind
listens for service requests at the port indicated in
the ``login'' service specification; see
.IR services (5).
When a service request is received the following protocol
is initiated:
.IP 1)
The server checks the client's source port.
If the port is not in the range 0-1023, the server
aborts the connection.
.IP 2)
The server checks the client's source address.
If the address is associated with a host for which no
corresponding entry exists in the host name data base (see
.IR hosts (5)),
the server aborts the connection.
.PP
Once the source port and address have been checked, 
.I rlogind
allocates a pseudo terminal (see 
.IR pty (4)),
and manipulates file descriptors so that the slave
half of the pseudo terminal becomes the 
.B stdin ,
.B stdout ,
and
.B stderr 
for a login process.
The login process is an instance of the
.IR login (1)
program, invoked with the
.B \-r
option.  The login process then proceeds with the authentication
process as described in
.IR rshd (8C).
If the remote user has an
.I equivalent
account, 
.I rlogind
allows the user to log in without giving a password. On the other hand,
if automatic authentication fails, 
.I rlogind 
reprompts the user
to login as one finds on a standard terminal line.
.PP
The parent of the login process manipulates the master side of
the pseduo terminal, operating as an intermediary
between the login process and the client instance of the
.I rlogin
program.  In normal operation, the packet protocol described
in
.IR pty (4)
is invoked to provide ^S/^Q type facilities and propagate
interrupt signals to the remote programs.  The login process
propagates the client terminal's baud rate and terminal type,
as found in the environment variable, ``TERM''; see
.IR environ (7).
.PP
If a session is inactive for more than 5 minutes, 
.I rlogind
terminates the session unless the remote host name is in the file
.I /etc/keeprlogin.
However, all sessions can be inactive for at most half an hour.
A session is inactive if there is no terminal I/Os.
.SH FORMAT OF /etc/keeprlogin
Each entry line in 
.I /etc/keeprlogin 
is an 
.I official 
name of the remote host from which inactive sessions are allowed to
last half an hour.
.SH DIAGNOSTICS
All diagnostic messages are returned on the connection
associated with the
.BR stderr ,
after which any network connections are closed.
An error is indicated by a leading byte with a value of 1.
.PP
.B ``Hostname for your address unknown.''
.br
No entry in the host name database existed for
the client's machine.
.PP
.B ``Try again.''
.br
A
.I fork
by the server failed.
.PP
.B ``/bin/sh: ...''
.br
The user's login shell could not be started.
.SH SEE ALSO
rshd(8C)
.SH BUGS
The authentication procedure used here assumes the integrity
of each client machine and the connecting medium.  This is
insecure, but is useful in an ``open'' environment.
.PP
.I Rlogind
supports at most 64 remote users.
It uses pseudo-terminals /dev/pty[pqrs][0-9a-f].
.PP
A facility to allow all data exchanges to be encrypted should be
present.

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