Time synchronisation is often a much underrated aspect of computer management. Generally time synchronisation is only crucial for networks or for computers that a take in time sensitive transactions across the internet.
Time synchronisation with modern operating systems such as Windows Vista, XP or the different versions of Linux is relatively easy as most contain the time synchronisation protocol NTP (Network Time Protocol) or a simplified version at least (SNTP).
NTP is an algorithm based program and works by using a single time source that can be distributed amongst the network (or a single computer) and is constantly checked to ensure the network’s clocks is running accurately.
For single computer users, or networks where security and precision are not primary concerns (although for any network security should be a main issue) then the simplest method of synchronising a computer is to use an internet time standard.
With a Windows operating system this can easily be done on a single computer by double clicking the clock icon and then configuring the internet time tab. However, it must be noted that in using an internet based time source such as nist.gov or windows.time, a port will have to be left open in the firewall which could be taken advantage of by malicious users.
For network users and those not wanting to leave vulnerabilities in their firewall then the most suitable solution is to use a dedicated network time server. Most of these devices also use the protocol NTP but as they receive a time reference externally to the network (usually by way of GPS or long wave radio) the leave no vulnerabilities in the firewall.
These NTP server devices are also far more reliable and accurate than internet time sources as they communicate directly with the signal from an atomic clock rather than being several tiers (in NTP terms known as strata) from the reference clock as most internet time sources are.