Network Time Services

Network Time Protocol

The Office of Information Technology provides centralized campus time services. The goals of the design are to have a secure time service that is accurate and available, and to invite all installations on campus to use this service. Previous time service on the ns.utah.edu and fiber.utah.edu servers was turned off in early 2005 and moved to a separate time.utah.edu server to which tighter security policies can be applied.

Configuration of NTP clients can occur in various ways depending on the environment in which it is used. There are configurations for stand alone machines, configurations for Windows Domain environments, configurations for Network Devices, etc. It is important to use NTP in the most appropriate deployment for your environment.

Stand-Alone NTP Clients

If you:

  • own, use or manage a computer and/or other networked equipment that supports the Network Time Protocol and
  • you want to provide it with a source of network time, and
  • your department does not recommend one,

please use time.utah.edu as your time source.

If you have been using one of ns.utah.edu or fiber.utah.edu as your network time source, you should change that reference now to prevent your clock from drifting.

If your application can make use of more than one source of time, please use time-a.utah.edu and time-b.utah.edu among your time sources. They are in two separate locations, reducing your exposure to network or power loss elsewhere on campus. Note that time.utah.edu is simply a DNS round-robin of time-a and time-b.

Windows XP:

Using Campus NTP servers with Windows XP

  • Right Click on the clock in the system tray of the task bar
  • Choose Adjust Date/Time
  • Choose Internet Time Tab
  • Add time.utah.edu to your server line.
  • Click Update Now to verify functionality
  • Choose OK

Unix Environments:

When configuring your ntp.conf file in Unix environments you may add lines such as the following.

  • server time-a.utah.edu
  • server time-b.utah.edu

The NTP service must be restarted in order to re-read the configuration file.

Some Linux distributions, such as SuSE, Red Hat, and Mandrake, may have a GUI interface to aid in this configuration.

Macintosh OS X:

Mac OS X uses ntpd internally to synchronize time, as done on other unix systems. Configuration is easiest via the System Preferences application.

  • Launch the System Preferences application.
  • From the View menu, select Date & Time.
  • Select the Network Time tab.
  • Check Use a network time server.
  • Enter a NTP Server of time.utah.edu.
  • Additional Mac NTP Information

LAN Administrators

If you are a LAN administrator and manage multiple machines NTP can be deployed in various ways.

Assignment via DCHP:

DHCP server option code 42 is available for the automatic assignment of NTP servers to DHCP clients. This is simply a listing of servers. If more than one server is in the list the servers should be listed in the order of preference.

Running NTP in a Windows Domain Environment:

Computers that are members of a domain act as a time client by default. It is important to configure your domain controller to request time from a campus time source. Please see this link for further details about configuring time services in a domain environment.


Time Service Administrators

If you run a stratum 2 or 3 ntp server that provides time to 50 or more computers or devices in your lab, department or college, consider peering with our stratum 2 timeservers. They are time01.it.utah.edu through time04.it.utah.edu and will not be directly accessible without prior arrangement. Besides each other, each currently sees five on-campus sources and three off-campus sources. Please contact OITSystems@lists.utah.edu in order to make these arrangements.

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For More Information