Time Servers and the Internet
Timing is becoming increasingly crucial for computer systems. It is now almost unheard of for a computer network to function without synchronisation to UTC (Coordinated Universal Time). And even single machines used in the home are now equipped with automatic synchronisation. The latest incarnation of Windows for instance, Windows 7, connects to a timing source automatically (although this application can be turned off manually by accessing the time and date preferences.)
The inclusion of these automatic synchronisation tools on the latest operating systems is an indication of how important timing information has become and when you consider the types of applications and transactions that are now conducted on the internet it is of no surprise.
Internet banking, online reservations, internet auctions and even email can be reliant on accurate time. Computers use timestamps as the only point of reference they have to identify when and if a transaction has occurred. Mistakes in timing information can cause untold errors and problems, particularly with debugging.
The internet is full of time servers with over a thousand time sources available for online synchronisation however; the accuracy and usefulness of these online sources of UTC time do vary and leaving a TCP/IP open in the firewall to allow the timing information through can leave a system vulnerable.
For network systems where timing is not only crucial but where security is also a paramount issue then the internet is not a preferred source for receiving UTC information and an external source is required.
Connecting a NTP network to an external source of UTC time is relatively straightforward if a network time server is used. These devices that are often referred to as NTP servers, use the atomic clocks onboard GPS (Global Positioning System) satellites or long wave transmissions broadcast by places such as NIST or NPL.
