CONCEPT
	imp

LAST UPDATED
	Deepthought, 10-Nov-92
	Pepel,	     18-Nov-93

DESRIPTION
	This document describes IMP, the intermud message protocol.

	Imp messages are exchanged between muds using UDP
	(unreliable datagram protocol) packets. Each mud provides
	a connection endpoint which is given by the ip host address
	and the UDP port number. Muds may then send messages to
	this port by using the efun send_imp(). The applied function
	receive_imp will be called by the driver in the master
	object if a imp message arrives at the mud's UDP port.

	Imp message packets have the following format:

	password@objectname@functionname[[@argument]...]

	<password> is the connection password to verify incoming
	imp packets. It is encoded using crypt(E) and compared to
	the stored password. Each mud participating in the imp 
	network has a secret password which is encoded by the
	admin and distributed to remote muds with which the mud
	should have direct connection. Encryted passwords may also
	propagated to other muds over already secure channels.

	<objectname> is a logical name which is not to be confused
	with mudlib object filenames. It is used by receive_msg in
	the master object to route the message to another object by
	associating the logical object name with a real mudlib file
	name. A good idea would be to reserve a special directory
	for imp objects, e.g. /secure/net/<objectname>.

	<functionname> is the function which is called by the master
	object in the object described by <objectname>. 

	<argument> are additional arguments which are handed to the
	function <functionname>. The exact definition of functions
	and arguments are left to the imp applications.

AUTHOR
	originally Deepthought

NOTE
	The above is only particularly correct nowadays. Recently a
	package name ``inetd'' was published, that is based on the IMP
	mechanism in the driver (send_imp() and receive_imp()), but
	it uses a different message format. That package seems to
	enjoy much publicity and is installed in a number of muds. For
	details look into the inetd description.

	An other method of inter mud connection is the Mudlink
	package, which uses a normal user connection that is connected
	to a special user object, and an auxiliary process that does
	the connection to other muds.

SEE ALSO
	send_imp(E), receive_imp(M)