How do I use pool.ntp.org?
If you just want to synchronise your computer's 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, 2, or 3 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.
Please also note that the system currently only provides IPv6 addresses for a zone in addition
to IPv4 addresses if the zone name is prefixed by the number 2, e.g. 2.pool.ntp.org
(provided there are any IPv6 NTP servers in the respective zone). Zone names not prefixed by a
number, or prefixed with any of 0, 1 or 3, currently provide IPv4 addresses only.
If you're using a recent Windows version, you can use the ntp client that is built into the system.
Right click the data time in system area and select Adjust Date/time or open up settings with Win+I and click Time & Language -> Date & Time.
scroll down and click Date, time, regional formatting
scroll down and click Additional date, time & regional settings
click Date and Time and Internet Time
click the Change settings button. Enter pool.ntp.org and click Update now.
Test by Right click the data time in system area and select Adjust Date/time or open up settings with Win+I and click Time & Language -> Date & Time. Click the "Sync now" button.
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.
Additional Notes
Consider if the NTP Pool is appropriate for your use. If business, organization or human life depends on having correct time or can be harmed by it being wrong, you shouldn't "just get it off the Internet". The NTP Pool is generally very high quality, but it is a service run by volunteers in their spare time. Please talk to your equipment and service vendors about getting local and reliable service setup for you. See also our terms of service. We recommend time servers from Meinberg, but you can also find time servers from End Run, Spectracom and many others.
If you have a static IP address and a reasonable Internet connection (bandwidth is not so important, but it should be stable and not too highly loaded), please consider donating your server to the server pool. It doesn't cost you more than a few hundred bytes per second traffic, but you help this project survive. Please read the joining page for more information.
If your Internet provider has a timeserver, or if you know of a good timeserver near you, you should use that and not this list - you'll probably get better time and you'll use fewer network resources. If you know only one timeserver near you, you can of course use that and two from pool.ntp.org or so.
It can rarely happen that you are assigned the same timeserver twice - just restarting the ntp server usually solves this problem. If you use a country zone, please note that it may be because there is only one server known in the project - better use a continental zone in that case. You can browse the zones to see how many servers we have in each zone.
Be friendly. Many servers are provided by volunteers, and almost all time
servers are really file or mail or webservers which just happen to also run ntp.
So don't use more than four time servers in your configuration, and don't play
tricks with burst or minpoll - all you will gain is extra
load on the volunteer time servers.
Make sure that the time zone configuration of your computer is correct. ntpd itself does not do anything about the time zones, it just uses UTC internally.
If you are synchronising a network to pool.ntp.org, please set up one of your computers as a time server and synchronize the other computers to that one. (you'll have some reading to do - it's not difficult though. And there's always the comp.protocols.time.ntp newsgroup.)
At this point, I'd like to thank those donating their time and timeservers to this network.