4.2 etc/rwhod Fix

[mike at Brl-Tgr.ARPA]

From:      Mike Muuss <mike at Brl-Tgr.ARPA>

This evening I added a new feature to the 4.2 BSD "rwhod"
daemon (which provides the information for ruptime and rwho).
While rwhod correctly detects the presence of broadcast network
hardware, and automaticly begins broadcasting it's status updates
on all locally connected broadcast interfaces, there is no way
to transmit information across a non-broadcast interface,
in particular across a network such as the ARPANET.

My new version of rwhod now also reads a file /etc/hosts.rwho,
which lists all hosts which are to be sent an individual copy
of the status datagrams.  While there is a cost associated with
doing this, the feeling of community that can result is probably
well worth it.

Of course, for information to flow both ways between a pair of hosts,
each must list the other one in their /etc/hosts.rwho file.
Clearly, traffic growth is n**2 with n = #line in /etc/hosts.rwho,
but...

Source and revised manual page availible on request by mail, or
they may be retrieved using anonymous FTP from host BRL-TGR,
file arch/rwhod.tar

	Best,
	 -Mike Muuss
	  U. S. Army BRL