Network Time Protocol Last Extension Field

Document Type Expired Internet-Draft (ntp WG)
Author Harlan Stenn 
Last updated 2016-09-15 (latest revision 2016-03-14)
Stream IETF
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state Candidate for WG Adoption
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This Internet-Draft is no longer active.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


NTPv4 is defined by RFC 5905 [RFC5905], and it and earlier versions of the NTP Protocol have supported symmetric private key MAC authentication. MACs pre-date the Extension Fields introduced in RFC 5905 [RFC5905], and as the number of Extension Fields grows there is an increasing chance of ambiguity when deciding if the "next" set of data is an Extension Field or a MAC. This proposal defines a new Extension Field which is used to signifiy that it is the last Extension Field in the packet. If present, any subsequent data SHOULD be considered to be a legacy MAC.


Harlan Stenn (

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