NTP

Network Time Protocol (NTP) is a protocol developed to work on TCP/IP, allowing a synchronization of time in a network, as radio satellite receiver, Global Positioning Service (GPS) or modem. It provides precision in a millisecond LAN's and until a few tens of milliseconds in WAN's (comparing with Coordinated Universal Time (UTC), through a GPS receptor, for example). NTP configuration uses many redundant servers and many different networks to achieve more precision and reliability.