NTP Time Servers in South Africa

Last updated 28 September 2022


Welcome to the The ZA Time Server pages, active since Feb 1999. These pages attempt to document all the aspects of accurate time keeping in the South African environment. It will point to resources maintained by several volunteers and also commercial institutions in South Africa.

These pages will probably remain under construction (or at least revision) indefinitely.


What is a time server?

Generally, a time server is a system which is accurately synchronized to UTC time (Universal Time, Co-ordinated). A time server can, in turn, provide accurate time to client machines that connect to it.

UTC can be obtained from a number of sources. In most countries one can use a radio clock and access the WWV and WWVB time signals. Other sources include GPS satellite receivers, dialup sources like ACTS and Ceasium beam frequency standard clocks. In South Africa, the most common source is the GPS receiver.


The first publicaly available NTP server in South Africa was put in operation by John Hay at the CSIR. The service started on a 486DX2-66 running BSD 2.2-current and xntpd 3.4e. You can read the original posting to the Usenet group za.net.misc when it was posted on June 18th, 1996. At the time it was synchronizing using a Rockwell MicroTracker LP GPS receiver. It ran continously without a problem or reboot until they had a long power failure in August 1997 that lasted longer than their UPS could keep it up. The machine was then upgraded to FreeBSD-2.2-STABLE and xntpd 3-5.90.3. This time the machine ran until December 30th, 1998 when there was another long power failure. On February 11th, 1999 the GPS receiver was damaged by lightning and it was configured to sync from some other stratum 1 sources until it was upgraded on March 17, 1999 to FreeBSD 4.0-current, ntp-4.0.92c and a Motorola Oncore UT+ GPS.

Usage Policy

Stratum-1 servers are still a scarce resource on the Internet. Most of these servers are not open to public use. It is considered bad form to use a Stratum-1 server directly to synchronise only one PC.

Stratum-2 servers obtain their time from a number of Stratum-1 servers. Using this methodology, the load on the primary servers can be reduced. The public can connect to stratum-2 servers and still obtain very accurate time. There are a number of these servers in SA (mostly provided by the bigger ISP's). In the list of Stratum-2 servers (below) the upstream ISP is also listed. Please use the Stratum-2 server that is logically closest to you.

Time Servers

Stratum-1 Servers (primaries for ZA)
Server Location Hosted by Upstream ISP OS Platform Source Clock
time.nmisa.org Pretoria NMISA TENET UNIX / FreeBSD ZA Master Clock
tick.meraka.csir.co.za Pretoria CSIR TENET UNIX / FreeBSD Motorola Oncore UT+ GPS
tock.meraka.csir.co.za Pretoria CSIR TENET UNIX / FreeBSD Motorola Oncore UT+ GPS
ntp01.cd.net.za Durban EDGECONNECT EDGECONNECT Hardware LeoNTP Server
ntp02.cd.net.za Durban EDGECONNECT EDGECONNECT Hardware FC-NTP-100 Server

Stratum-2 Servers
Server DNS name Location Hosted by OS Platform Upstream ISP
ntp1.meraka.csir.co.za Pretoria CSIR FreeBSD Internet Solutions
ntp.dimensiondata.com Johannesburg Dimension Data Linux Dimension Data
ntp2.dimensiondata.com Cape Town Dimension Data Linux Dimension Data
igubu.saix.net Cape Town SAIX Solaris SAIX
ntp.mtnbusiness.co.za Cape Town MTN Business FreeBSD MTN Business
ntp1.inx.net.za Johannesburg JINX Ubuntu inx-za
ntp2.inx.net.za Cape Town CINX Ubuntu inx-za
ntp3.inx.net.za Durban DINX Ubuntu inx-za
ntp4.inx.net.za Johannesburg JINX Ubuntu inx-za
ntp5.inx.net.za Cape Town CINX Ubuntu inx-za
ntp1.cd.net.za Durban EDGECONNECT Debian EDGECONNECT
ntp2.cd.net.za Durban EDGECONNECT Debian EDGECONNECT
ntp1.nog.net.za Durban Zanog FreeBSD Zanog
ntp2.nog.net.za Cape Town Zanog FreeBSD Zanog

Please note that the above list does not indicate any of the servers to be public access servers. We are in the process of gathering access policies from the administrators of each system in order to publish them here.

How to sync Windows machines

Windows 2000 Pro and Windows XP Pro have built-in time synchronisation clients. I am not talking about the infamous "Internet Time" in XP, but rather about real time. To activate time-sync on your favorite windows workstation, follow these steps:

Windows 7 has a different way of configuring NTP from the command-line.

If you are behind a firewall (which I hope you are if you are using a Microsoft product), your firewall must allow UDP packets to go out to port 123 and allow UDP packets to return from port 123 to your machine. Most proper firewalls (PIX, FreeBSD, Linux Netfilter) will allow this type of behaviour unless specifically denied by your administrator.

Remember, ask your network administrator first before applying this, since you may already have your own internal time server available.

Other NTP sites in South Africa

ZA-Time Mailing list

The za-time list is a discussion group centered around time synchronization in South Africa. It will focus on NTP, SNTP and other means of synchronization via the Internet, but will also cover any other methods of obtaining time signals in South Africa.

In short:

To subscribe, send a blank message to


To make a posting to the za-time list, send to


E-mail comments to or visit me.