NAME
	  rlogind - The	remote login server

     SYNOPSIS
	  rlogind [-aln]

     FLAGS
	  -a   Requests	the addresses for the hostname,	verifying that
	       the name	and address correspond.	 Normal	authentication
	       is bypassed if the address verification fails.

	  -l   Prevents	authentication based on	the user's
	       $HOME/.rhosts file, unless the user is logging in as
	       the superuser.

	  -n   Disables	transport-level, keep-alive messages. The mes-
	       sages are enabled by default.

     DESCRIPTION
	  The rlogind daemon is	the server for the rlogin(1) program.
	  The server provides a	remote login facility with authentica-
	  tion based on	privileged port	numbers	from trusted hosts.

	  The rlogind daemon listens for service requests at the port
	  indicated in the login service specification;	see
	  services(4). When a service request is received, the follow-
	  ing protocol is initiated:

	  1.   The server checks the client's source port.  If the
	       port is not in the range	512 to 1023, the server	aborts
	       the connection.

	  2.   The server checks the client's source address and
	       requests	the corresponding hostname (see
	       gethostbyaddr(3), hosts(4) and named(8)). If the	host-
	       name cannot be determined, the dot-notation representa-
	       tion of the host	address	is used.  If the hostname is
	       in the same domain as the server	(according to the last
	       two components of the domain name), or if the -a	flag
	       is given, the addresses for the hostname	are requested,
	       verifying that the name and address correspond.	Normal
	       authentication is bypassed if the address verification
	       fails.

	  Once the source port and address have	been checked, rlogind
	  proceeds with	the authentication process described in
	  rshd(8). It then allocates a pseudoterminal (see pty (4)),
	  and manipulates file descriptors so that the slave half of
	  the pseudoterminal becomes the stdin,	stdout,	and stderr for
	  a login process.  The	login process is an instance of	the
	  login(1) program invoked with	the -f option if authentica-
	  tion has succeeded.  If automatic authentication fails, the
	  user is prompted to log in as	if on a	standard terminal
	  line.	 The -l	option prevents	any authentication based on
	  the user's .rhosts file, unless the user is logging in as
	  the superuser.

	  The parent of	the login process manipulates the master side
	  of the pseudoterminal, operating as an intermediary between
	  the login process and	the client instance of the rlogin pro-
	  gram.	 In normal operation, the packet protocol described in
	  pty(4) is invoked to provide <Ctrl-s>/<Ctrl-q> type facili-
	  ties 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 TERM environment vari-
	  able;	see environ (7). The screen or window size of the ter-
	  minal	is requested from the client, and window size changes
	  from the client are propagated to the	pseudoterminal.

	  Transport-level, keep-alive messages are enabled unless the
	  -n flag is present.  The use of keep-alive messages allows
	  sessions to be timed out if the client crashes or becomes
	  unreachable.

	  Note that 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.

     DIAGNOSTICS
	  All initial diagnostic messages are indicated	by a leading
	  byte with a value of 1 (one),	after which any	network	con-
	  nections are closed.	If there are no	errors before login is
	  invoked, a null byte is returned as in indication of suc-
	  cess.

	  Try again.
	  A fork by the	server failed.

     FILES
	  /usr/sbin/rlogind
	       Specifies the command path

     RELATED INFORMATION
	  Commands: login(1)

	  Routines: ruserok(3)

	  Daemons: rshd(8)