Last updated: 27 October 2009, 8:51am EDT (GMT -0400)
The PublicNTP Project is a not-for-profit endeavor operating under a simple premise: providing sources of highly-accurate time benefits everyone with a negligble cost for the provider. Such sources of time should be offered at no cost to any and all consumers who wish to partake as a public good.
Open-access information systems that were designed and are operated primarily for the common good, such as the Global Positioning System and the root servers for the Domain Name System.
29 July 2009: When this project started in the spring of 2008, the two currently-active servers (SJC1 and ORD2) provided time service to roughly 300 active clients combined. As of late July 2009 that number has grown to nearly 500, an increase of 60% in just 16 months.
25 July 2009: The usage stats for stratum2.ord2 have been wrong for awhile. After finally getting a minute to look into the problem, it turns out the service was a "victim" of its own success. If the monitoring program that ships with NTP tries to maintain stats when more than 600 people have used the service it dies. I've switched to using the very useful scripts provided by Wayne Schlitt and sanity has returned to the usage data.
20 June 2009: A bug in the NTP server when running on a 64-bit x86 version of FreeBSD was causing the ORD2 server to not be as accurate as it could/should be. After limiting the maximum time between server polls, ORD2's UTC variance has been improved by an order of magnitude (from +/- ~100 microseconds to +/- ~10 microseconds).
15 March 2008: The ord1 server in Chicago has been delisted.
13 February 2008: PublicNTP Project launched with one server in the San Francisco, California area and two servers in Chicago, Illinois.
All the project servers operate at NTP stratum two, meaning they synchronize across the network with three or more independent systems that maintain very accurate time. These systems are directly connected to high-quality time sources, such as GPS and CDMA (cell phone system) receivers, that differ from Coordinated Universal Time (UTC) by less than a microsecond (10-6, or 0.000001, seconds). It's uncommon for any of the project servers below to vary more than one millisecond (0.001 seconds) from UTC.
| Hostname | Location | Datacenter | Timezone | Live Date | Notes |
| stratum2.sjc1.publicntp.net | Santa Clara, California, USA | Layer42 | PST (GMT -0800) | 13 February 2008 | |
| stratum2.ord2.publicntp.net | Chicago, Illinois, USA | Steadfast | CST (GMT -0600) | 13 February 2008 | IPv6 service will be available in fall 2009 |
Various statistics from the Project servers, including usage and accuracy information.
The project provides highly-accurate time to clients using version 4 of the Network Time Protocol served up by a version of the NTP daemon, an open-source project hosted by the Internet Systems Consortium.
If the project name isn't enough of a hint, these are public, open-access time servers. Come one, come all (with a few caveats; see the Abuse section below). The bandwidth and CPU costs of running public NTP servers are small and and we don't mind paying them.
We're very interested in establishing peering sessions with others servers in stratum two. Please contact us to establish authenticated peering connections.
Again, these servers are run as a hobby in our spare time. We make no claims regarding uptime or accuracy of the responses we return. We pride ourselves on maintaining the system quite well considering the time and financial commitments that are currently possible. With that said, you're not likely to be able to measure our uptime in two nines, much less five. The project organizers stress that clients should always make sure to synchronize their systems with at least four or five stable, independently-managed time servers to increase their overall fault-tolerance.
All project servers are proud to participate in the NTP Pool Project. All are members of the root pool, the North American continent pool and the United States country zone.
This service is and will always be a hobby. As time passes, we fully hope and plan to purchase and host additional stratum one and two servers in underserved (in terms of open-access NTP sources) regions across the country ... and hopefully, eventually, the globe.
We doubt we'll ever get servers deployed in as many locations as the Internet Systems Consortium's F-Root nameserver, but it's not a bad goal to keep in mind.
We've got the servers set up to do rate-limiting. If you send requests too often you'll find that the servers will get sick of the harassment rather quickly and will ignore further connections until your rate drops back down to something less obnoxious. As long as you're being fairly sane and waiting 60 seconds or more between requests everything will be copacetic.
If you'd like to contact the project administrators, email us at timekeeper@publicntp.net.