Definition: In computer networking, NTP is a system to synchronize time of day computer clocks across the Internet.
NTP is based on Internet timeservers, computers with access to atomic clocks such as those operated by the U.S. government. These NTP servers run a software service that provides the clock’s time of day to client computers over UDP port 123. NTP supports a hierarchy of multiple server levels to handle a large load of client requests. The protocol includes algorithms to accurately adjust the time of day being reported to account for Internet network transmission delays.