Internet Assigned Numbers Authority

Network Time Protocol (NTP) Parameters

Created
2010-03-25
Last Updated
2023-05-03
Available Formats

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Registries included below

NTP Reference Identifier Codes

Registration Procedure(s)
First Come First Served
Reference
[RFC5905]
Note
Codes beginning with the character "X" are reserved for experimentation and 
development. IANA cannot assign them.
Available Formats

CSV
ID Clock Source Reference
GOES Geosynchronous Orbit Environment Satellite [RFC5905]
GPS Global Position System [RFC5905]
GAL Galileo Positioning System [RFC5905]
PPS Generic pulse-per-second [RFC5905]
IRIG Inter-Range Instrumentation Group [RFC5905]
WWVB LF Radio WWVB Ft. Collins, CO 60 kHz [RFC5905]
DCF LF Radio DCF77 Mainflingen, DE 77.5 kHz [RFC5905]
HBG LF Radio HBG Prangins, HB 75 kHz [RFC5905]
MSF LF Radio MSF Anthorn, UK 60 kHz [RFC5905]
JJY LF Radio JJY Fukushima, JP 40 kHz, Saga, JP 60 kHz [RFC5905]
LORC MF Radio LORAN C station, 100 kHz [RFC5905]
TDF MF Radio Allouis, FR 162 kHz [RFC5905]
CHU HF Radio CHU Ottawa, Ontario [RFC5905]
WWV HF Radio WWV Ft. Collins, CO [RFC5905]
WWVH HF Radio WWVH Kauai, HI [RFC5905]
NIST NIST telephone modem [RFC5905]
ACTS NIST telephone modem [RFC5905]
USNO USNO telephone modem [RFC5905]
PTB European telephone modem [RFC5905]
DFM UTC(DFM) [DFM_AS][Jürgen_Appel]

NTP Kiss-o'-Death Codes

Registration Procedure(s)
First Come First Served
Reference
[RFC5905]
Note
Codes beginning with the character "X" are reserved for experimentation and 
development. IANA cannot assign them.
Available Formats

CSV
Code Meaning Reference
ACST The association belongs to a unicast server [RFC5905]
AUTH Server authentication failed [RFC5905]
AUTO Autokey sequence failed [RFC5905]
BCST The association belongs to a broadcast server [RFC5905]
CRYP Cryptographic authentication or identification failed [RFC5905]
DENY Access denied by remote server [RFC5905]
DROP Lost peer in symmetric mode [RFC5905]
RSTR Access denied due to local policy [RFC5905]
INIT The association has not yet synchronized for the first time [RFC5905]
MCST The association belongs to a dynamically discovered server [RFC5905]
NKEY No key found. Either the key was never installed or is not trusted [RFC5905]
NTSN Network Time Security (NTS) negative-acknowledgment (NAK) [RFC8915, Section 5.7]
RATE Rate exceeded. The server has temporarily denied access because the client exceeded the rate threshold [RFC5905]
RMOT Alteration of association from a remote host running ntpdc. [RFC5905]
STEP A step change in system time has occurred, but the association has not yet resynchronized [RFC5905]

NTP Extension Field Types

Registration Procedure(s)
IETF Review
Reference
[RFC5905]
Available Formats

CSV
Field Type Meaning Reference
0x0002 No-Operation Request [RFC5906]
0x0104 Unique Identifier [RFC8915, Section 5.3]
0x0204 NTS Cookie [RFC8915, Section 5.4]
0x0304 NTS Cookie Placeholder [RFC8915, Section 5.5]
0x0404 NTS Authenticator and Encrypted Extension Fields [RFC8915, Section 5.6]
0x8002 No-Operation Response [RFC5906]
0xC002 No-Operation Error Response [RFC5906]
0x0102 Association Message Request [RFC5906]
0x8102 Association Message Response [RFC5906]
0xC102 Association Message Error Response [RFC5906]
0x0202 Certificate Message Request [RFC5906]
0x8202 Certificate Message Response [RFC5906]
0xC202 Certificate Message Error Response [RFC5906]
0x0302 Cookie Message Request [RFC5906]
0x8302 Cookie Message Response [RFC5906]
0xC302 Cookie Message Error Response [RFC5906]
0x0402 Autokey Message Request [RFC5906]
0x8402 Autokey Message Response [RFC5906]
0xC402 Autokey Message Error Response [RFC5906]
0x0502 Leapseconds Message Request [RFC5906]
0x8502 Leapseconds Message Response [RFC5906]
0xC502 Leapseconds Message Error Response [RFC5906]
0x0602 Sign Message Request [RFC5906]
0x8602 Sign Message Response [RFC5906]
0xC602 Sign Message Error Response [RFC5906]
0x0702 IFF Identity Message Request [RFC5906]
0x8702 IFF Identity Message Response [RFC5906]
0xC702 IFF Identity Message Error Response [RFC5906]
0x0802 GQ Identity Message Request [RFC5906]
0x8802 GQ Identity Message Response [RFC5906]
0xC802 GQ Identity Message Error Response [RFC5906]
0x0902 MV Identity Message Request [RFC5906]
0x8902 MV Identity Message Response [RFC5906]
0xC902 MV Identity Message Error Response [RFC5906]
0x2005 Checksum Complement [RFC7821]

Contact Information

ID Name Organization Contact URI Last Updated
[DFM_AS] DFM A/S https://dfm.dk 2023-05-03
[Jürgen_Appel] Jürgen Appel DFM A/S mailto:jap&dfm.dk 2023-05-03