Introduction

What is a MUD?

A MUD (Multi-User Dungeon) is a text-based multiplayer world accessed over the internet. Players connect to a MUD server and interact entirely through written text: you read descriptions of rooms, type commands to move and act, and see the results as text output. There are no graphics – everything is conveyed through words, sometimes with color, and sometimes ASCII or ANSI art.

MUDs are the direct ancestors of modern graphical MMORPGs like World of Warcraft and EverQuest. The first MUD was created in 1978 by Roy Trubshaw and Richard Bartle at the University of Essex. Hundreds of MUDs remain active today, many maintained by volunteer communities large and small that have kept them running for decades.

Types of Servers

The term “MUD” is used loosely to describe many kinds of text-based multiplayer servers. They vary widely in purpose:

MUD (Multi-User Dungeon)

The original type. Focused on combat, exploration, quests, and character advancement, usually in a fantasy or science fiction setting. Common codebase families include DikuMUD, LPMud, and ROM.

MUSH (Multi-User Shared Hallucination)

Focused on collaborative storytelling and roleplay rather than combat mechanics. Players can build rooms and objects using an in-game scripting language. Common codebases include PennMUSH, TinyMUSH, and RhostMUSH.

MUX (Multi-User eXperience)

Similar to MUSHes, based on the TinyMUX codebase. Often used for freeform roleplay games set in licensed universes (superhero comics, TV shows, etc.).

MOO (MUD, Object-Oriented)

A programmable virtual environment where the world is built from objects with attached code. LambdaMOO is the most well-known example.

MUCK (Multi-User Created Kingdom)

Social and creative environments where players build areas and write programs in MUF (Multi-User Forth). Fuzzball MUCK is the dominant codebase. MUCKs are popular in the furry community.

Talker

Someone quickly figured out they could just remove the dungeon from a MUD codebase and have a basic “chat server”, A text-based chat system with rooms but minimal or no game mechanics.

What is Telnet?

Telnet is a network protocol from 1969 (RFC 854) that establishes a two-way text connection over the internet. Despite its age, Telnet remains widely deployed and used all over the world for embedded systems. Its longevity comes from its simplicity: it is portable, accessible, and easy to develop for, which is why MUD communities have adopted it for so long.

When you connect to a MUD, your client opens a TCP connection to the server’s address and port number (for example, achaea.com on port 23). The server sends text for you to read, and you type commands that are sent back.

Although telnet supports option negotiation, a majority of the servers surveyed do not perform any Telnet option negotiation at all – they simply send and receive raw text ASCII text. Many MUD codebases predate general Unicode support and may emit non-ASCII data (such as accented characters or box-drawing symbols) in legacy encodings.

Adult Content

Some of the most popular servers in this census by player count are not traditional games at all – they are adult chat rooms.

About This Site

This site is mainly for people looking for a MUD to play, to provide a search interface and to learn about them without connecting to them, individually.

But it is also for MUD “archaeologists” and TELNET negotiation nerds. It was created by the author of the Python telnetlib3 library, and, uses the telnetlib3-fingerprint client to gather it.

The list of MUDs scanned is from the github-managed file, mudlist.txt