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 separate locations and obtain their time using a combination of external sources and GPS 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:
18.104.22.168 22.214.171.124 126.96.36.199 188.8.131.52
Please note that the IP addresses 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