Mud Server Status Protocol  
MUDhalla is a website dedicated to multiplayer text adventure games, also known as MUDs.
MUD listings are often out dated and lack accurate information. Verifying that the one submitting a new MUD is a member of the MUD's administration can be quite tedious as well.
The MUD Server Status Protocol seeks to address these issues by providing a transparant protocol for MUD crawlers to gather detailed information about a MUD, including dynamic information like boot time and the current amount of online players. It also makes submitting a new mud entry very simple because it only requires a player or admin to fill in the hostname and port.
This document provides a technical description of the MSSP protocol.

The MSSP Protocol

MSSP is implemented as a Telnet option RFC854, RFC855. The server and client negotiate the use of MSSP as they would any other telnet option. Once agreement has been reached on the use of the option, option sub-negotiation is used to send information about the server to the client.

Server Commands

IAC WILL MSSP    indicates the server supports MSSP.

Client Commands

IAC DO   MSSP    indicates the client supports MSSP.
IAC DONT MSSP    indicates the client doesn't support MSSP.

Handshake

When a client connects to a server the server should send IAC WILL MSSP. The client should respond with either IAC DO MSSP or IAC DONT MSSP. If the server receives IAC DO MSSP it should respond with: IAC SB MSSP MSSP_VAR "variable" MSSP_VAL "value" MSSP_VAR "variable" MSSP_VAL "value" IAC SE.
The quote characters mean that the encased word is a string, the quotes themselves should not be send.

MSSP definitions

MSSP 70

MSSP_VAR 1
MSSP_VAL 2

Example MSSP handshake

server - IAC WILL MSSP
client - IAC DO MSSP
server - IAC SB MSSP MSSP_VAR "PLAYERS" MSSP_VAL "52" MSSP_VAR "UPTIME" MSSP_VAL "1234567890" IAC SE

Variables and Values

For ease of parsing, variables and values cannot contain the MSSP_VAL, MSSP_VAR, IAC, or NUL byte. The value can be an empty string unless a numeric value is expected in which case the default value should be 0. If your Mud can't calculate one of the numeric values for the World variables you can use "-1" to indicate that the data is not available. If a list of responses is provided try to pick from the list, unless "Etc" is specified, which means it's open ended.
The same variable can be send more than once with different values, in which case the last reported value should be used as the default value. It is up to the crawler to decide how to exactly process multiple values. It's also possible to attach several values to a single variable by using MSSP_VAL more than once, with the default value reported last. This would look as following:
IAC SB MSSP MSSP_VAR "PORT" MSSP_VAL "80" MSSP_VAL "23" MSSP_VAL "3000" MSSP_VAR "CREATED" MSSP_VAL "1996" IAC SE
The quote characters mean that the encased word is a string, the quotes themselves should not be send.
Variable names should exist of upper case letters and may contain spaces. As many programming languages have difficulties with variable names which contain spaces clients and crawlers can substitute spaces with underscores as the recommended solution.


Official MSSP Variables

Required

NAME               Name of the MUD.

PLAYERS            Current number of logged in players.

UPTIME             Unix time value of the startup time of the MUD.
Generic

CODEBASE           Name of the codebase, eg Merc 2.1. You can report multiple codebases using the array
                   format, make sure to report the current codebase last.

CONTACT            Email address for contacting the MUD.

CRAWL DELAY        Preferred minimum number of hours between crawls. Send -1 to use the crawler's default.

CREATED            Year the MUD was created.

DISCORD            URL to a Discord server, this should include the https:// prefix.

HOSTNAME           Current or new hostname.

ICON               URL to a square image in bmp, png, jpg, or gif format. The icon should be equal or
                   larger than 64x64 pixels, with a filesize no larger than 256KB.

IP                 Current or new IP address.

IPV6               Current or new IPv6 address.

LANGUAGE           English name of the language used, eg German or English

LOCATION           English short name of the country where the server is
                   located, using ISO 3166.

MINIMUM AGE        Current minimum age requirement, omit if not applicable.

PORT               Current or new port number. Can be used multiple times, most important port last.

REFERRAL           A list of other MSSP enabled MUDs for the crawler to check using the host port
                   format and array notation. Adding referrals is important to make MSSP decentralized.
                   Make sure to separate the host and port with a space rather than : because IPv6
                   addresses contain colons.

SSL                The port number for a SSL (Secure Socket Layer) encrypted connection.

WEBSITE            URL to MUD website, this should include the http:// or https:// prefix.
Categorization

FAMILY             AberMUD, CoffeeMUD, DikuMUD, Evennia, LPMud, MajorMUD, MOO, Mordor, SocketMud,
                   TinyMUD, TinyMUCK, TinyMUSH, Custom.
                   
                   Report Custom unless it's a well established family.

                   You can report multiple generic codebases using the array format, make sure to report the
                   most distant codebase (aka the family) last.

                   Check the MUD family tree for naming and capitalization.

GENRE              Adult, Fantasy, Historical, Horror, Modern, Mystery, None, Romance, Science Fiction, Spiritual

GAMEPLAY           Adventure, Educational, Hack and Slash, None, Player versus Player, Player versus Environment,
                   Questing, Roleplaying, Simulation, Social, Strategy

STATUS             Alpha, Closed Beta, Open Beta, Live
GAMESYSTEM         D&D, d20 System, World of Darkness, Etc.

                   Use Custom if using a custom gamesystems. Use None if not available.

INTERMUD           AberChat, I3, IMC2, MudNet, Etc.

                   Can be used multiple times if you support several protocols, most important protocol last.
                   Leave empty or omit if no Intermud protocol is supported.

SUBGENRE           Alternate History, Anime, Cyberpunk, Detective, Discworld, Dragonlance, Christian Fiction, Classical Fantasy,
                   Crime, Dark Fantasy, Epic Fantasy, Erotic, Exploration, Forgotten Realms, Frankenstein, Gothic, High Fantasy,
                   Magical Realism, Medieval Fantasy, Multiverse, Paranormal, Post-Apocalyptic, Military Science Fiction,
                   Mythology, Pulp, Star Wars, Steampunk, Suspense, Time Travel, Weird Fiction, World War II, Urban Fantasy, Etc.

                   Use None if not applicable.
World

AREAS              Current number of areas.
HELPFILES          Current number of help files.
MOBILES            Current number of unique mobiles.
OBJECTS            Current number of unique objects.
ROOMS              Current number of unique rooms, use 0 if roomless.

CLASSES            Number of player classes, use 0 if classless.
LEVELS             Number of player levels, use 0 if level-less.
RACES              Number of player races, use 0 if raceless.
SKILLS             Number of player skills, use 0 if skill-less.
Protocols

ANSI               Supports ANSI colors ? 1 or 0
UTF-8              Supports UTF-8 ? 1 or 0
VT100              Supports VT100 interface ?  1 or 0
XTERM 256 COLORS   Supports xterm 256 colors ?  1 or 0
XTERM TRUE COLORS  Supports xterm 24 bit colors ? 1 or 0
Commercial

PAY TO PLAY        Pay to play ? 1 or 0
PAY FOR PERKS      Pay for perks ? 1 or 0
Hiring

HIRING BUILDERS    Game is hiring builders ? 1 or 0
HIRING CODERS      Game is hiring coders ? 1 or 0
Links

Contact

If you want a link added, or added MSSP to your Mud, you can email me at mudclient@gmail.com. I'll add muds that correctly report a substantial section of the official variables to the MSSP crawler.

Debugging

You can use the TinTin++ MUD client to display MSSP output from a MUD server.
After launching the client you need to enter '#config telnet debug' and to create a connection enter '#session mssp <hostname> <port>'. To exit press ctrl-d.
For additional debug information you can save the mssp debug script to a text file in the directory from which you launched tintin, for example 'debug.tin'. Use '#read debug.tin' to load the script into tintin. If you are using WinTin++ you need to save the file in the /bin/ directory. The WinTin++ folder in the Windows start menu contains a link to the tintin directory.

Clients

TinTin++ Mud Client
Mudlet the MUD client

Codebases

BasedMUD - DikuMUD/ROM - As of version 1.5.
Evennia - As of version 0.8.
FluffOS - LpMUD - As of version 2.16.
Lowlands - DikuMUD/MrMud - As of version 1.4.
NekkidMUD - SocketMUD/NakedMud - As of version 1.5.
PennMUSH - As of version 1.8.4p1.
WickedMUD - SocketMUD - As of version 1.0

Directories

Grapevine
MSSP Mud Crawler
MudStats (defunct)
MudVerse

Telnet Servers

A list of MSSP enabled MUDs including debug information is available on the MSSP Mud Crawler page. MUDs need to be listed on TMC in order to be automatically added.

Discussion

MUDhalla Discord channel for TELNET related discussion

Snippets

KaVir's MUD Protocol Handler - Handles ATCP, CHARSET, MSDP, MSSP, MSP, MXP links, NAWS, TTYPE, UTF-8 and 256 colors.
PennMUSH MSSP - MSSP Patch for the PennMUSH codebase.
Scandum's MUD Telopt Handler - Handles CHARSET, EOR, MCCP2, MCCP3, MSDP, MSDP over GMCP, MSSP, MTTS, NAWS, NEW-ENVIRON, TTYPE, and xterm 256 colors.