Time synchronization with network time protocol servers (NTP servers) is now a common consideration for network administrators, although, keeping exact time as told by an atomic clock on a computer network is often seen as unnecessary by some administrators
So what are the advantages of synchronizing to an atomic clock and is it necessary for your computer network? Well the advantages of having accurate time synchronization are manifold but it is the disadvantages of not having it that are most important.
UTC time (Coordinated Universal Time) is a global timescale that is kept accurate by a constellation of atomic clocks from all over the world. It is UTC time that NTP time servers normally synchronize too. Not just that it provides a very accurate time reference to for computer networks to synchronize too but also it is used by millions of such networks across the globe therefore synchronizing to UTC is equivalent to synchronizing a computer network to every other network on the globe.
For security reasons it is imperative that all computer networks are synchronized to a stable time source. This doesn’t have to be UTC any single time source will do unless the network conducts time sensitive transactions with other networks then UTC becomes crucial otherwise errors may occur and these can vary from emails arriving before they were despatched to loss of data. However, as UTC is governed by atomic clocks it makes it a highly accurate and auditable source of time.
Some network administrators take the shortcut of using an internet time server as a source of UTC time, forgoing the need for a dedicated NTP device. However, there are security risks in doing such a thing. Firstly, the inbuilt security mechanism used by NTP, called authentication, which confirms a time source is where and who it claims it is, is unavailable across the internet. Secondly, internet time servers are outside the firewall which means a UDP port needs to be left open to allow the time signal traffic. This can be manipulated by malicious users or viral programs.
A dedicated NTP time server is external to the network and receives the UTC atomic clock time from with either the GPS satellite system (global positioning system) or specialist radio transmissions broadcast by national physics laboratories.