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

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 from them.

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 any difficulty.

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:

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, 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

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 ( 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 ( 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 ( of

The most recent versions of these FAQs are archived at and on in the news.answers archives.

Andrew Cowan /