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Network Time Protocol — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Network_Time_Protocol
License (as archived): CC-BY-SA-4.0
Archived: 2026-10-15T15:35:05.138Z
SHA-256 of the archived text: 53245ce1458ead98c33dee834c01ca339a1fe2fc9667ee70a141eac61957ddb8
Stable URL of this page: https://metraipolis.com/documento/dc_3a4dfd782838

How to cite

Network Time Protocol — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Network_Time_Protocol (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_3a4dfd782838 (Metraipolis archive dc_3a4dfd782838, sha256 53245ce1458ead98c33dee834c01ca339a1fe2fc9667ee70a141eac61957ddb8)

BibTeX

@misc{dc3a4dfd782838,
  title = {Network Time Protocol — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Network_Time_Protocol},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_3a4dfd782838; sha256 53245ce1458ead98c33dee834c01ca339a1fe2fc9667ee70a141eac61957ddb8},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Network_Time_Protocol. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in current use. NTP was designed by David L. Mills of the University of Delaware. NTP is intended to synchronize participating computers to within a few milliseconds of Coordinated Universal Time (UTC). It uses the intersection algorithm, a modified version of Marzullo's algorithm, to select accurate time servers and is designed to mitigate the effects of variable network latency. NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions. Asymmetric routes and network congestion can cause errors of 100 ms or more. The protocol is usually described in terms of a client–server model, but can as easily be used in peer-to-peer relationships where both peers consider the other to be a potential time source. Implementations send and receive timestamps using the User Datagram Protocol (UDP); the service is normally on port number 123, and in some modes both sides use this port number. They can also use broadcasting or multicasting, where clients passively listen to time updates after an initial round-trip calibrating exchange. NTP supplies a warning of any impending leap second adjustment, but no information about local time zones or daylight saving time is transmitted. The current protocol is version 4 (NTPv4), which is backward compatible with version 3.

Tema degli esploratori: fiducia digitale e crittografia (deposito sistematico; ricerca «timestamping»).
Fonte: Wikipedia in inglese, voce «Network Time Protocol» — https://en.wikipedia.org/wiki/Network_Time_Protocol
Wikidata Q217491 (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q217491
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Network_Time_Protocol?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1375597400, consultata il 2026-10-15T14:58:55.633Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: eaac88e0e9ea9f00a56e131e5dd6e8c90d26f44b1cdf31bbc5ecdd9f69e901b2