Player-session MUD protocol

ZMP

Zenith MUD Protocol

Legacy compatibility Not in common current use Legacy

A generic bidirectional named-command protocol with package conventions for identity, capabilities, ping, time, and application messages.

Protocol overview

First seen: Circa 2003
Present-day status: Legacy compatibility
In use today?: No common current use was verified.
Legacy?: Yes. It may still matter for compatibility or historical systems.
Layer: Player-session MUD protocol
Transport: Telnet option 93 with NUL-delimited command arguments
Telnet option: 93
Research validated: 2026-08-29

Current use and fit

Preserved and still available in a few implementations, but largely superseded by GMCP and MSDP.

Implementation essentials

The server initiates WILL ZMP.
Frame command and arguments with NUL delimiters inside Telnet subnegotiation.
Escape IAC and preserve display ordering.

Compatibility and safety notes

Implementations must cope with large subnegotiations.
Do not design a new general protocol namespace around ZMP.

Original specifications and sources

MUD Standards preservation Preservation

Where an original site has disappeared, a preservation archive is linked and identified as such. MUDVerse does not claim authorship of the original protocol.