Network Time Protocol (And the NTP Pool)
The Network Time Protocol is, as the name implies, a standard for syncronising time across networks. This is extremely useful as it allows all computer clocks to be syncronised to a common, correct time rather than being “around” a certain time. It’s especially useful on servers, where co-ordinating events or tracing failures needs precision and accuracy.
So how can you sync your computer with a NTP time server? It’s actually quite simple;
- Windows – Windows XP and higher already sync out of the box to time.windows.com, however time.windows.com may be very far from you and hence there is a delay in the time making it less accurate. If you want to change the server, double click the clock (XP, on Vista double click and select “Change Time and Date Settings”), then click the Internet time tab, enter the server (XP, on Vista click Change Settings) and click Update Now to sync.
- Linux – Use the command ntpdate followed by the NTP server you want to sync with
So, how do you go about choosing a better NTP source for windows and a source for linux? Enter the NTP Pool.
There are quite a few “Stratum 1” NTP servers, which get their time directly from cesium clocks or GPS satellites, these are the most accurate sources of time available. However, if we all synced with a stratum 1 server, they would quickly be overloaded. Most people don’t need that kind of precision, so enter “Stratum 2” servers. Stratum 2 servers NTP sync with “Stratum 1” servers, so while they are not as exact as they are, they are only different by a few milliseconds – hardly a problem. Hence, you should sync with a “Stratum 2” server. But how do you find one? The NTP pool is a pool, a collection of NTP servers intended for the masses to sync with. Either use 0.pool.ntp.org as your NTP sync source, or if you want extra accuracy select your continent, then country from the right to get a server closer to you. Now you can enjoy accurate time!
However, the demands upon the NTP pool grow daily, but not it’s supply of pooled servers. If you have a server with some spare bandwidth and a static ip address that is available 24/7, donate a server to the pool. You can adjust the amount of NTP traffic you get by setting your bandwidth in the control panel, even home users can participate as long as they meet the requirements!