Ancillary or client protocol

MPCP

MUD Proxy Communication Protocol

Experimental / unproven Not in common current use Legacy

A draft shared-secret authentication mechanism between a MUD proxy and server.

Protocol overview

First seen: Date not established
Present-day status: Experimental / unproven
In use today?: No common current use was verified.
Legacy?: Yes. It may still matter for compatibility or historical systems.
Layer: Ancillary or client protocol
Transport: Draft Telnet option 202 using HMAC-SHA1
Telnet option: 202
Research validated: 2026-08-29

Current use and fit

No verified production implementation was found, and the archived specification questions whether one existed.

Implementation essentials

Use modern TLS and current authentication designs instead.
Retain the document only for historical study.

Compatibility and safety notes

HMAC-SHA1-era shared-secret deployment is not a suitable new security baseline.
Draft option numbers do not establish interoperability.

Original specifications and sources

MUD Standards draft preservation Draft

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