About NTP

Network Time Protocol (NTP) servers are fundamental to network management, for they permit synchronizing the clocks of the hooked equipment from a reference accepted worldwide, known as UTC (Universal Time Coordinated). The Internet’s wide range makes time synchronization crucial for the exchange of information among thousands of computers operating on a 24x7 basis, that is to say, 24 hours a day, seven days a week. The benefits of using NTP reach both users and network administrators. On the users’ side, synchronization of the computer clocks can be vital in certain operations.

Let’s take as an example handing in someone’s income tax declaration. Suppose it is the last day to do it and the clock of the machine hosting the Federal Reserve website is a minute fast. The deadline is 8:00 p.m. In this very plausible case, any declaration handed in after 7:59 p.m. will be rejected, causing harm to the contributor. One or two-minute delays are quite frequent when an NTP scheme is not used.

Benefíts of NTP service

From the point of view of network administration, the use of NTP has many advantages since it permits the automatic synchronization of all the equipment that is hooked up. In other words, the administrator does not have to go from machine to machine setting the local clock. Besides, security is reinforced with clock synchronization of the equipment hooked up, for the investigation of attacks to computers depends on checking the logs in different machines. The inconsistency of the time recorded by each machine makes this work impossible.

NTP hierarchy

NTP implements a model of synchronization hierarchically distributed. On the top, there are the stratum 1 time servers, computers directly connected to high precision devices known as "reference clocks" (or stratum 0 servers). Typically, these devices can be atomic clocks, GPS (Global Positioning Systems) receivers or radio receivers. Any NTP server having as a time reference a stratum 1 server becomes a stratum 2; any NTP server having as a time reference a stratum 2 server becomes a stratum 3, and so on.