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rlogind(8)

NAME

     rlogind -- remote login server

SYNOPSIS

     rlogind [-Daln]

DESCRIPTION

     The rlogind utility is the server for the rlogin(1) program.  The server
     provides a remote login facility with authentication based on privileged
     port numbers from trusted hosts.

     Options supported by rlogind:

     -D      Set TCP_NODELAY socket option.  This improves responsiveness at
	     the expense of some additional network traffic.

     -a      Ask hostname for verification.

     -l      Prevent any authentication based on the user's ``.rhosts'' file,
	     unless the user is logging in as the superuser.

     -n      Disable keep-alive messages.

     The following options are valid only if Kerberos is in use:

     -k      Enable Kerberos authentication.

     -v      Enable vacuous mode.

     -x      Enable DES encryption for all data passed via the rlogin session.
	     This may impact response time and CPU utilization, but provides
	     increased security.

     The rlogind utility listens for service requests at the port indicated in
     the ``login'' service specification; see services(5).  When a service
     request is received the following protocol is initiated:

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

     2.   The server checks the client's source address and requests the cor-
	  responding host name (see gethostbyaddr(3), hosts(5) and named(8)).
	  If the hostname 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 option is given, the addresses for the
	  hostname are requested, verifying that the name and address corre-
	  spond.  Normal authentication is bypassed if the address verifica-
	  tion fails.

     Once the source port and address have been checked, rlogind proceeds with
     the authentication process described in rshd(8).  It then allocates a
     pseudo terminal (see pty(4)), and manipulates file descriptors so that
     the slave half of the pseudo terminal 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 authentication has suc-
     ceeded.  If automatic authentication fails, the user is prompted to log
     type, as found in the environment variable, TERM; see environ(7).	The
     screen or window size of the terminal is requested from the client, and
     window size changes from the client are propagated to the pseudo termi-
     nal.

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

DIAGNOSTICS

     All initial diagnostic messages are indicated by a leading byte with a
     value of 1, after which any network connections are closed.  If there are
     no errors before login(1) is invoked, a null byte is returned as in indi-
     cation of success.

     Try again.
	     A fork(2) by the server failed.

SEE ALSO

     login(1), ruserok(3), hosts(5), hosts.equiv(5), login.conf(5),
     nologin(5), services(5), rshd(8)

FILES

     /etc/hosts
     /etc/hosts.equiv
     $HOME/.rhosts
     /var/run/nologin

BUGS

     The authentication procedure used here assumes the integrity of each
     client machine and the connecting medium.	This is insecure, but is use-
     ful in an ``open'' environment.

     A facility to allow all data exchanges to be encrypted should be present.

     A more extensible protocol should be used.

HISTORY

     The rlogind utility appeared in 4.2BSD.

     IPv6 support was added by WIDE/KAME project.

FreeBSD 5.4			 June 4, 1993			   FreeBSD 5.4

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