MUD

Before the internet, the popular text-based computer game “Zork”) let single players fight monsters in randomly populated “dungeons”.
With the advance of computer networking, multi-player variants named “Multi-User Dungeons” were created, or “MUDs”.
Today the term is used for all kinds of text-based multi-player games, whether their setting might be medieval fantasy, sci-fi, post-apocalyptic, horror or something else.
Other variants of text-based communities are called MUSH, MUX, MOO etc. - but because the lines between these “MU*” can be blurry, and /notes/mu* doesn’t make for a good URL, my note here is about all of the mentioned variants.

Resources

RFC 855: Telnet Option Specifications
Generic Mud Communication Protocol (GMCP)
- Uses Telnet code 201
- Mudlet tutorial - last updated 2013-02
- Mudlet thread
- TinTin++ documentation
- MUSHclient documentation
- Iron Realms documentation
Map protocol (MMP)
- Mudlet documentation
MUD Client Media Protocol (MCMP)
- Mudlet documentation
Achaea Telnet Client Protocol (ATCP)
- Developed in 2008
- Uses Telnet code 200
- Replaced by GMCP
Mud Server Data Protocol (MSDP)
- Developed in 2009
Mud Client Compression Protocol (MCCP)
Mud Master Chat Protocol (MMCP)
Aardwolf channel 102