Common Time Server Questions

What is a time server?

A time server is a device that utilises a single time source and distributes it amongst a network. This enables all machines on a LAN (or WAN) to be synchronised together.

What is NTP?

Network Time Protocol is a protocol (a set of instructions) designed to distribute the time from a time server top a network.

Why do I need a time server?

It may well be that you don’t. Many small networks survive and operate perfectly without the need of a time server. However, if computers are required to do time sensitive transactions or applications then a time server is essential. Without proper synchronisation all sorts of unforeseen problems can arise and many of the online transactions that we take for granted such as seat reservation, Internet shopping, the stock exchange and even sending emails are reliant on perfect time synchronisation.

What is the best time reference to use?

A single global timescale based on the time told by atomic clocks has been developed called UTC (Coordinated Universal Time). UTC is utilised by networks all over the world. In using UTC you are in affect synchronising your network with every other network in the world that utilises UTC.

Where to I get UTC time from?

The most common and easiest location to receive UTC time is from across the Internet although Internet time sources are notoriously inaccurate. They also provide little security. Apart from the fact the time server is outside your firewall, NTP can’t authenticate these signals. Authentication is a security measure used by NTP to prevent malicious attacks that masquerade as a time server.

The most secure methods for receiving UTC time is by using either the GPS network (global positioning system), whose satellites transmit the timing information or alternatively by using specialist national time and frequency long-wave transmissions although these are not available everywhere.