Network Time Protocol (NTP) Parameters
- Created
- 2010-03-25
- Last Updated
- 2020-10-05
- 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] |
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] |