Network Time Protocol

The Network Time Protocol (NTP) is a protocol for distributing the Coordinated Universal Time (UTC) by synchronizing the clocks of computer systems over IP networks. 

NTP is one of the oldest Internet Protocols still in use (since before 1985) and uses UDP port 123. 

References



Other websites

 NTP Public Services Project This is the home for the NTP (Network Time Protocol) Public Services Project which provides public support for the NTP Project and the IETF NTP Working Group.  Also a Wiki with lists of NTP servers.   
 IETF NTP working group
 David Mills' NTP project page
 NTP version 4 Release Notes
 Time and NTP paper
 NTP Articles and News  - A collection of NTP related articles and news
 NTP Survey 2005 
 Network Time Protocol  - National Research Council of Canada
 Network Time Server - NTP time server software for Windows
 Online NTP Test Utility - Tests a NTP Server which is public to the internet
 A Brief Guide to NTP  - Google Knol on NTP
 Time Synchronisation Blog 

Other time synchronization protocols
 Daytime protocol DAYTIME synchronization protocol via TCP or UDP port 13
 ICMP protocol Time synchronization with ICMP timestamps (basis for timed  )
 HTTP Time Protocol (HTP) Time synchronization with HTTP headers
 Reference-Broadcast Synchronization  (RBS)  Time synchronization for wireless networks
 Time protocol Time synchronization protocol via TCP or UDP port 37

Category:Internet protocols