An Acronym for Network Time Protocol.

A protocol that allows synchronising a computer's internal clock (and system time) with an external source, such as a computer with a more accurate clock. Machines that are synchronised with an atomic clock or GPS are stratum 1. Machines that synchronise to these machines are stratum 2, and so on. Normally stratum 1 machines aren't available for public connections.

NTP in NewZealand

Have a look at http://www.cosc.canterbury.ac.nz/research/reports/TechReps/1999/tr_9901.pdf for a scientific study (from 1999) of the topology of the country's main NTP servers. (A bit dated as GPS is much more widely available now).

There is a pool of NewZealand servers at nz.pool.ntp.org, which provides RoundRobin DNS access to publicly accessible NTP servers that have agreed to be part of the pool.

Stratum 1 NTP servers in NewZealand

The Measurements Standards Laboratory at Industrial Reasearch Limited run a HP5071A caesium atomic clock which is part of the New Zealand time standard. This server is available at the address msltime.irl.cri.nz. Read more details.

TelstraClear generously provides a stratum 1 NTP server for public use:

bigben.clix.net.nz

However, you really shouldn't synchronise to a stratum one server for your small network -- if everyone did that then the server would probably need too much bandwidth. Please read http://list.waikato.ac.nz/pipermail/nznog/2001-October/003705.html. The difference in accuracy between synching to a stratum 1 server and a lower stratum server is negligible!

For example, read http://www.cs.wisc.edu/plonka/netgear-sntp/ -- in summary, NetGear hard-coded a public NTP server into some of their consumer products, which eventually ended up using hundreds of Mbits/second of the university's bandwidth, even after they were forced to shut down the server.

Other NTP Servers

Some NewZealand ISPs have NTP servers for their customers:

• ntp.iprolink.co.nz
• ntp.iconz.co.nz
• tk1.ihug.co.nz to tk3.ihug.co.nz
• time.paradise.net.nz

or you could try querying your ISP's DNS servers with ntp or ntp1.

Many of NewZealand's Universities also have public time servers such as:

• ntp.public.otago.ac.nz (Please notify before using)
• ntp.massey.ac.nz (Use the DNS name, as its IP changed recently and is now hosted by two machines)

For a long time WaikatoUniversity had public NTP servers. They are still available but no longer publicly accessible.

NZ Pool

Your best bet for a small home or office network is to set your server to nz.pool.ntp.org or pool.ntp.org, which will use RoundRobin DNS to choose one of the many servers now registered with that project.

German NTP servers

If you live in Germany (or somewhere close by) you may want to try this list:

• time1.rrz.uni-koeln.de
• time2.rrz.uni-koeln.de
• time3.rrz.uni-koeln.de
• ts-1.rz.rwth-aachen.de
• ntp1.t-online.de
• www1.rrz.uni-koeln.de
• hora.cs.tu-berlin.de
• rustime01.rus.uni-stuttgart.de
• rzfs2.rz.tu-bs.de
• ns1.hrz.uni-giessen.de
• ntp2-rz.rrze.uni-erlangen.de
• mailbox.tu-berlin.de
• ntps1-0.cs.tu-berlin.de
• ntp0.fau.de
• ntp1.fau.de
• ntp2.fau.de
• ntp3.fau.de
• ptbtime1.ptb.de
• ptbtime2.ptb.de

You might also want to look at a very extensive list of public German NTP servers.

Other non-NZ servers

As mentioned above, pool.ntp.org is a RoundRobin DNS for many NTP servers. Try cc.pool.ntp.org, where cc is a CountryCode?.

• A list of stratum 1 time servers
• A list of the stratum 2 time servers

See also:

• ntpd(1)
• ntpdate(1)
• hwclock(8)

Part of CategoryNetworking