The pool.ntp.org project is a big virtual cluster of timeservers providing reliable easy to use NTP service for millions of clients.
The pool is being used by millions or tens of millions of systems around the world. It's the default "time server" for most of the major Linux distributions and many networked appliances (see information for vendors).
Because of the large number of users we are in need of more servers. If you have a server with a static IP address always available on the internet, please considering adding it to the system.
The project is maintained and developed by Ask Bjørn Hansen and a great group of contributors on the mailing lists. The code is available.
Hosting and bandwidth for the "hub" servers are currently provided by Develooper, Phyber Communications and YellowBot.
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If you are IPv6 connected, the www.pool.ntp.org site will now be delivered to you via IPv6.
I did tests on a hundred thousand visitors to the site and nobody who could connect with IPv4 had trouble talking to a site with both "AAAA" and "A" records. The test only included users with javascript however, so it could still miss appliances, older boxes etc. More tests are needed to make the pool.ntp.org service "ipv6 enabled".
In our ongoing process of getting the NTP Pool IPv6 compatible we took a first (small!) step getting the website partially available via IPv6. For now it's via an IPv6-only hostname: www6.ntppool.org.
So far the anecdotal reports are that it's working fine for people with IPv6. The next tests will be to see how connectivity is affected for everyone else if a host has both AAAA (IPv6) and A (IPv4) records in DNS.
As part of the same change, the website is now served through Varnish which makes it a bit faster and more importantly makes it inconsequential when people rudely try to "sync time" via HTTP to the server.
The pool keeps growing (although we still need more servers).
Recently we've added zones and servers in Costa Rica, Venezuela, Serbia, Croatia, El Salvador and New Caledonia.
But we need more servers all over the world. In smaller developing countries internet use is picking up and local servers will help. In bigger countries usage is also growing faster than the number of servers; so extra help is needed. We're getting close to 2000 [active servers] - but for millions and millions of users we need more.
Sometimes I’m asked if the NTP Pool really needs more servers. The answer is yes, always!
While the number of servers has grown nicely over the years, so has the number of users so we need
The only (tricky) requirement is that you have a static IP address and expect the server (and IP) to be around for a long time. ntpd doesn’t deal well with changing IP addresses (yet), so this is important.
It really depends on which country you are in; but you can heavily regulate it with the “netspeed” setting in the server settings on the manage page. As a rule of thumb you’ll get 1/3 query a second “per megabit”; with peaks of about 1 to 1.5 queries per second per megabit at the top of each hour (yeah, lots of people are unhelpfully synchronizing their time at the hour each hour). Each packet is only about 50 bytes, so this is very little traffic. If you set the netspeed to for example 1 mbit (the default) you’ll get very little traffic but still help tens of thousands of users a day set their time.
In some countries you might get more queries; but that just means that the need for your server is greater in that country!
As mentioned a few months ago, NTP operates exclusively with UTC time. If your system is (typically) one hour off after syncing with the NTP Pool then it's because your operating system needs to be configured with the correct timezone and daylight saving time setting. If you live in a place that recently changed rules for daylight saving time you need to make sure you have the latest system updates installed.