NTP (Network Time Protocol) is a protocol that allows computers, servers, and network devices to synchronize their clocks with each other. NTP uses a hierarchical structure where the most accurate time source is referred to as stratum 1. Computers or network devices that use the stratum 1 source will become stratum 2. It is possible to use multiple NTP sources, in that case, the NTP client will figure out which time source it will use to synchronize itself with. These lessons explain how NTP works and how to configure it.