What is a time server?
A time server is a device that receives and distributes a single time source across a computer network for the purposes of time synchronization. These devices are often referred to as a NTP server, NTP time server, network time server or dedicated time server.
NTP – Network Time Protocol is a set of software instructions designed to transfer and synchronize time across LANs (Local Area Network) or WANS (Wider Area Network). NTP is one of the oldest known protocols in use today and is by far the most commonly used time synchronization application.
What timescale should I use?
Coordinated Universal Time (UTC) is a global timescale based on the time told by atomic clocks. UTC doesn’t take into account time zones and is therefore ideal for network applications as in principle by synchronizing a network to UTC you are in effect synchronizing it to every other network that utilises UTC.
Where does a time server receive the time from?
A time server can utilise the time from anywhere such as a wrist watch or wall clock. However, any sensible network administrator would opt to use a source of UTC time to ensure the network is as accurate as possible. UTC is available from several ready sources. The most used is perhaps the internet. There are many ‘time servers’ on the internet that distribute UTC time. Unfortunately, many are not at all accurate an in using an internet time source you could be leaving the network vulnerable as malicious users can take advantage of the open port in the firewall where the timing information flows.
It is far better to use a dedicated NTP time server that receives the UTC time signal external to the network and firewall. The best methods for doing this is to either use the GPS signals transmitted from space or the national time and frequency transmissions broadcast by several countries in long wave.