1. The University NTP Service

Accurate time synchronisation across computer networks is important for time-stamping in security systems, reliable log-scanning to analyse security breaches, and the maintenance of consistency in distributed file systems.

NTP is designed to be highly fault-tolerant. For this purpose it is best for a machine to be obtain time from a number of different servers.

IT Services provide four time servers, available to any Oxford IPv4 host. These are located at four seperate locations and obtain their time using a combination of external sources, GPS signals and MSF radio signals .

Where possible, please use the following four DNS names: ntp0.ox.ac.uk, ntp1.ox.ac.uk, ntp2.ox.ac.uk, ntp3.ox.ac.uk

In ntp.conf format this would be

server  ntp0.ox.ac.uk    # IT Services NTP server
server  ntp1.ox.ac.uk    # IT Services NTP server
server  ntp2.ox.ac.uk    # IT Services NTP server
server  ntp3.ox.ac.uk    # IT Services NTP server

A DNS round robin of ntp.ox.ac.uk exists for the above if your device will only accept one entry.

If the configuration of your device will not accept a DNS name, the IPv4 addresses are:

129.67.1.160
129.67.1.164
163.1.2.160
163.1.2.164

Please note that the IP addresess of NTP servers may occasionally be subject to change, although IT Services will endeavour to minimise the frequency of such changes. Notice will be given to the itss-announce mailing list.

NTP is defined in RFC 1305, Network Time Protocol (version 3)

If you wish to use an external source in addition, we suggest using uk.pool.ntp.org

No IPv6 address for this service is officially provided yet, we hope to finalise this is the second quarter of 2013.

2. Historical Service Addresses

The NTP service was once more complex with seperate stratums and an enforced hierarchy. There are a large number of devices in the university using the older service addresses and so to this end the older DNS names and addresses are maintained for the time being to reduce workload on IT staff university-wide.

The following addtional addresses are currently supported but should not be entered in new configuration:

ntp4.ox.ac.uk      has address 163.1.2.168
ntp0.oucs.ox.ac.uk has address 129.67.1.4
ntp1.oucs.ox.ac.uk has address 163.1.2.4
ntp2.oucs.ox.ac.uk has address 163.1.2.5
ntp3.oucs.ox.ac.uk has address 129.67.1.5

A DNS round robin of ntp.oucs.ox.ac.uk exists for the historical stratum 3 service.