How do I use pool.ntp.org?

If you just want to synchronise your computers clock to the network, the configuration file (for the ntpd program from the ntp.org distribution, on any supported operating system - Linux, *BSD, Windows and even some more exotic systems) is really simple:

driftfile /var/lib/ntp/ntp.drift server 0.pool.ntp.org server 1.pool.ntp.org server 2.pool.ntp.org server 3.pool.ntp.org

The 0, 1, 2 and 3.pool.ntp.org names point to a random set of servers that will change every hour. Make sure your computer's clock is set to something sensible (within a few minutes of the 'true' time) - you could use ntpdate pool.ntp.org , or you could just use the date command and set it to your wristwatch. Start ntpd, and after some time (this could take as long as half an hour!), ntpq -pn should output something like:

$ ntpq -pn remote refid st t when poll reach delay offset jitter ============================================================================== +81.6.42.224 193.5.216.14 2 u 68 1024 377 158.995 51.220 50.287 *217.162.232.173 130.149.17.8 2 u 191 1024 176 79.245 3.589 27.454 -129.132.57.95 131.188.3.222 3 u 766 1024 377 22.302 -2.928 0.508

The IP addresses will be different, because you've been assigned random timeservers. The essential thing is that one of the lines starts with an asterisk ( * ), this means your computer gets the time from the internet - you'll never have to worry about it again!

Looking up pool.ntp.org (or 0.pool.ntp.org , 1.pool.ntp.org , etc) will usually return IP addresses for servers in or close to your country. For most users this will give the best results.

You can also use the continental zones (For example europe, north-america, oceania or asia.pool.ntp.org), and a country zone (like ch.pool.ntp.org in Switzerland) - for all these zones, you can again use the 0, 1 or 2 prefixes, like 0.ch.pool.ntp.org. Note, however, that the country zone might not exist for your country, or might contain only one or two timeservers.

If you're using a recent Windows version, you can use the ntp client that is built into the system. As administrator enter

w32tm /config /syncfromflags:manual /manualpeerlist:"0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org 3.pool.ntp.org"

at the command prompt. This will work on Windows 2003 and newer. If you use an older version of windows you can try

net time /setsntp:"0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org"

The same can be achieved by, as administrator, right-clicking the clock in the taskbar, selecting 'Adjust Date/Time' and entering the server name in the 'Internet Time' tab.

Meinberg made a port of the ntp daemon for windows.

If your Windows system is part of a domain, you might not be able to independently update your computer time. For more information about setting the time on windows, see How Windows Time Service Works.