TCPSERV(1)		(Nonessential Utilities)		TCPSERV(1)



NAME
	tcpserv - TCP/IP protocol based generic server

SYNOPSIS
	tcpserv [-f max] [-d] [-t] [-u|-n] port [program [arguments]]

DESCRIPTION

	This program acts as a remote server for any command specified
on the command line.  It binds the command to the port specified in the
command line, and waits for a connection.  When it recieves a connection,
it runs a subprocess that provides full duplex communication between the
program, which is attatched to a psuedo-tty, and the remote client (like
telnet).  The pseudo-tty is originally set using the parameters set by 
'stty sane'.  any additional settings must be done by the program.
It can theoretically handle any number of connections, but realistically,
it is limited by the number of processes allowed and the number of 
pseudo-tty's available.  Once the connection is passed to the program,
'tcpserv' goes back to waiting in the background for a connection.
It is a good idea to invoke 'tcpserv' in the background, ie:
	tcpserv port program arguments &

Options:	-t	Allows tcpserv to support telnet connections.  
			The telnet protocol handling is very simple as
			tcpserv is not meant to be a pure telnet client.

		-u	Tells tcpserv to write a utmp entry for each
			connection.  The utmp entry is written using
			the username of the person who invoked tcpserv.

		-d	Tells tcpserv to run in daemon mode.  In this
			mode, tcpserv breaks away from your terminal
			and runs in the background.  It stays in the
			current working directory, and keeps the full
			environment it started with, while accepting
			tcp connections.

		-n      Tells tcpserv to run a login(1) emulator on 
			the port.  This login feature will prompt for
			the login name, password, and look them up in
			the passwd file.  It then performs all of the
			steps of login(1), except writing wtmp and
			lastlog entries.  If no program is set to run,
			then the connection's user's login shell will
			be run.  If tcpserv is running with superuser
			permissions, the program will run as though
			the logging in user had logged in via telnet,
			in their home directory, with their permissions,
			etc.  If tcpserv is not running as superuser,
			the results are unpredictable;  the program
			will run with the tcpserv invoker's permissions.

 		-f max	Sets 'max' as the maximum number of simultaneous
			connections tcpserv will allow.

		-x	Sets debug mode.  Standard error redirected to
			tcpserv's controlling terminal, not to the 
			pseudo-tty.  This is usefull to see what is
			happening to programs that just quit.  In this
			debug mode, telnet negotiation is shown, and
			the hostname of each attempted connection is
			also shown.


	WARNING! tcpserv does NO inherent security checking.  Any
security must be provided by the program passed to tcpserv.  The program 
that the remote server interacts with, inherits the environment the that
the user who started tcpserv had.  ie: if the person ran
	'tcpserv 8000 sh &'
and had as his prompt "Yes? ", anyone who telneted to that person's
system and to port 8000 would connect to a shell that presented the 
prompt "Yes? " to them.  It would also run with the priveleges and as a
process of the person who invoked 'tcpserv'. (Unless that person was
root, and the program on the command line used setuid() to set the user
id to something else)




NOTES
	The input from the remote program is passed transparently to the
	program under the pty.  No protocol checking is done, and no out
	of band communcations are interpreted.