Network Time Protocol Version 4 (NTPv4) Extension Fields

Document Type Expired Internet-Draft (ntp WG)
Authors Harlan Stenn  , David Mills 
Last updated 2019-09-27 (latest revision 2019-03-26)
Stream Internent Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state Dead WG Document
Polled for WG adoption but not adopted
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Network Time Protocol version 4 (NTPv4) defines the optional usage of extension fields. An extension field, as defined in RFC 5905 [RFC5905] and RFC 5906 [RFC5906], resides after the end of the NTP header and supplies optional capabilities or information that cannot be conveyed in the basic NTP packet. This document updates RFC 5905 [RFC5905] by clarifying some points regarding NTP extension fields and their usage with legacy Message Authentication Codes (MACs), and removes wasteful requirements added by RCF 7822 [RFC7822]. This proposal deprecates RFC 7822 [RFC7822]. RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH BEFORE PUBLISHING: The source code and issues list for this draft can be found in


Harlan Stenn (
David Mills (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)