If you are reading this then you are probably aware of the importance time plays in IT systems and computer networks. Most computer administrators appreciate that precise time and accurate synchronisation are an important aspect of keeping a computer network error free and secure.
And yet, despite its importance many network administrators still rely on the Internet as a source of UTC time for their networks (UTC – Coordinated Universal Time), primarily because they see it as a quick and more importantly a free method of time synchronisation.
However, the drawbacks in using these free services may cost a lot more than the money saved on a dedicated NTP time server.
NTP (Network Time Protocol) is now present on nearly all computers and it is NTP that is used to synchronise computer systems. However, if an Internet time source is used then the source is outside the network firewall and this creates a serious vulnerability. Any external time source will require a port to be left open in the firewall to allow the time information packets through and this opening is too easy a way to exploit a network which can become victim to a DDOS attack (Distributed Denial of Service) or even allow malicious programmes through to take control of the machines themselves.
Another problem is the availability of stratum 1 time sources across the internet. Most online time sources come from stratum 2 time servers. These are devices that receive the time from a time server (stratum 1) that originally gets the information from an atomic clock (stratum 0). While stratum 2 devices can be just as accurate as stratum 1 time servers, across the internet without NTP authentication the actual accuracy can not be guaranteed.
Furthermore, internet time sources have never been considered accurate or precise with surveys showing over half being inaccurate by over a second and the rest dependent on the distance from client as to whether they can provide any useful accuracy. Even organisations such as NIST publish advisory notices on their time server pages about it unable to guarantee security or accuracy and yet millions of networks are still receiving time from across the internet.
With the decline in cost of dedicated radio referenced NTP time servers or GPS NTP server there has never been a better time to get one. And when you consider the cost of a computer breach or crashed network the NTP server will have paid for itself many times over.