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Subject: [rec.games.mud]: FAQ #3/4: RWHO and "mudwho"
This article was archived around: Mon, 17 Sep 2001 00:25:26 -0000
FREQUENTLY ASKED QUESTIONS: Basic Information on RWHO and mudwho
This is part 3 in a 4 part series of FAQs.
Disclaimer: This document may be seen to be biased towards
TinyMUDs. This is because the original author of this document
mainly plays those types of servers, not because she thinks they
are inherently better or worse than other types of servers.
However, this document is meant to be generalized and useful for
all MUDdom, and so corrections and contributions are always
welcome. The new maintainers will be gradually modifying the FAQ to
be geared towards all of the various server types.
Note: This section of the MUD FAQ is not currently being
maintained. The two links included in section 3.3 are now obsolete
and I was unable to find alternative locations. If anyone knows
where to find new locations please email the FAQ maintainer and I
will update this document accordingly.
Table of Contents
* 3.1. What is RWHO?
* 3.2. How Does It All Work?
* 3.3. Where Can I Get This Stuff?
* 3.4. Where Are Some RWHO Servers?
RWHO and mudwho
3.1. What is RWHO?
RWHO stands for Remote WHO. It's a way of getting a WHO list from a
MUD, without even having to connect to that MUD at all. Anyone can get
this output from a RWHO server (an mwhod), by using straight telnet to
connect to a certain port (6889), or by using the client program
mudwho. RWHO servers talk to other mwhods, passing information
around, and are talked to directly by some MUDs, receiving information
Any one mwhod keeps track of several MUDs, plus storing information
passed it from other mwhods. Only MUDs that have the RWHO routines
compiled in will be able to send their WHO list info to a mwhod.
UnterMUDs have this capability built in; other MUDs have to have the
routines installed first. The RWHO routines have been installed into
TinyMUSH, TinyMUCK, LPMUD, DikuMUD, and AberMUD, as well as the
Nightmare 2.5, TMI2, and Lima mudlibs for LPMUD without encountering
3.2. How Does It All Work?
mwhod is the RWHO server that runs on a particular host and keeps a
list of known MUDs. It is initially primed with a list of "trusted"
MUDs and passwords used for authentication, and will accept
information about who is logged into those MUDs. The server also has a
notion of a "peer" server, which can transfer it (occasionally) a copy
of all of its list of who is logged on, and where. The idea is that
the whole MUDding community could probably be served pretty well by
about 5 peer mwhods that kept each other up to date about what each
one is seeing.
Communication between mwhods (and server updates sent to mwhods) is
done with UDP datagrams, since they're fast, nonblocking, and
throw-away. (RWHO information is considered to be interesting but not
vital information, if you get my drift). Each MUD server only sends
updates to a single mwhod, which may then propagate that information
to its peers. This is done within the MUD server as follows:
* whenever the server boots, it sends a "hi there" packet to the
mwhod, telling it that it's up and running.
* whenever a player connects, it sends a "so and so is here" packet
to the mwhod, telling it that the user has connected.
* whenever a player disconnects, it sends a "so and so left" packet
to the mwhod, telling it to delete the entry.
* every so often ("so often" being defined as a time agreed upon by
the mwhod's owner, and the MUD's wizard, usually every 5 minutes
or so) the MUD sends a "hi there" packet and a complete list of
everyone that is on, just to refresh the mwhod's idea of who is
logged into that MUD.
If a user connects to a specific port (6889) of a host machine running
an mwhod they are given a formatted dump of the mwhod's current table
of MUDs and players, and then disconnected. mudwho is a simple little
program that contacts an mwhod and downloads this information.
Ideally, the functionality of mudwho would be built into a player's
client software, for ease of use. Two handy options can be used by
mudwho, if the netlag to the mwhod server isn't too bad. The options
are -u <username>, and -m <mudname>. If received before the timeout,
the mwhod will then only dump WHO list information for the specified
player or MUD.
The mwhod does some clever stuff as far as eventually timing
information about of its tables - for example, if it hears absolutely
nothing from a MUD for a certain amount of time, it will mark the MUD
as down. Player entries are expired similarly. The design is based on
the idea that we'll use UDP to just fling information out and hope it
sticks, and then let the recipient clean it up, rather than to develop
a more complex protocol based on TCPs and timeouts. To prevent a
packet circular send situation, each entry that is sent is given a
"generation" number, which is incremented by one each time it is
forwarded along. In this manner, a MUD server might send a "so and so
is here" (generation zero) to its local mwhod. The local mwhod will
eventually send a copy to any peers it may have (generation one), and
so forth. Part of the initial table that an mwhod uses to establish
what peers it trusts contains a generation value, and it will neither
accept nor propagate information to a specific peer that is of a
higher generation value. This way, a "tree" of servers could
theoretically be constructed, with the highest level one having a
total view of a large MudIverse.
3.3. Where Can I Get This Stuff?
The RWHO routines can be ftp'd from decuac.dec.com, in pub/mud.
Included is a HOW_TO file, which describes how to plug the routines
into a MUD server, and also where to ask for a mwhod to use.
The mwhod program itself can also be found on decuac, but there is
currently little need for another one running in the USA, except
perhaps as a backup. There is, however, only one running in all of
Europe, and further expansion may need to be made in that area.
3.4. Where Are Some RWHO Servers?
Updated 12/28/99 - we have been informed that the only known RWHO
server is no longer running. So, the only answer we can provide is
that we do not know. If you have any information about RWHO servers
that are still running please email us at email@example.com.
This posting has been generated as a public service, but is still
copyrighted 1996-1999 by Jennifer Smith. Modifications made after
August, 1999 are copyrighted 1999 by Andrew Cowan. If you have any
suggestions, questions, additions, comments or criticisms
concerning this posting, contact Andrew Cowan
(firstname.lastname@example.org). Other Frequently Asked Questions (FAQ)
postings contain information dealing with clients, servers, RWHO,
and FTP sites. While these items aren't necessary, they are quite
useful. I'd also like to thank cthonics (email@example.com) for his
help in writing these FAQs, ashne and Satoria for their help, and
everyone else for helpful comments and suggestions. Thanks again to
Alec Muffett (firstname.lastname@example.org) of alt.security.
The most recent versions of these FAQs are archived at
http://www.mudconnect.com/mudfaq/ and on rtfm.mit.edu in the
Andrew Cowan / email@example.com