This document describes the Network Time Protocol (NTP) Service available to the UChicago campus community. This service is used to centrally sync the clocks of computers, network servers, and other devices that reside on UChicago networks—doing so ensures accurate time for log reporting. Synchronized time and logging is imperative for issue correlation and problem resolution.
The intended audience for this document is anyone who wishes to synchronize their device clock with the campus time service while on the campus network. It is important to note that the NTP service is not available when off campus and is therefore discouraged for use for transient devices such as laptops, phones, and other portable devices. Please see the Transient Devices section for guidance on laptops, etc.
The Campus NTP Service is comprised of four total devices as well as a number of off-site peers. IT Services owns and operates a local Stratum 1 clock that uses GPS as a source. Along with this GPS, the clock affirms its accuracy by peering with GPS clocks operated by other institutions as well as the US Military. Along with the GPS clock, ITS operates a trio of dedicated Stratum 2 NTP Servers, outlined below, that provide the campus community with a reliable source for time. These NTP servers both synchronize and peer with the GPS clock, each other, and other external NTP servers to ensure a high degree of accuracy. Devices should be configured to sync with all three NTP Servers, where possible, to ensure consistent synchronization in the event a singular device is down for maintenance or hardware failure.
| Name | Hostname | IPv4 Address | IPv6 Address | UDP Port |
|---|---|---|---|---|
| net-ntp00 | net-ntp00.uchicago.edu | 128.135.105.108 | TBD | 123 |
| net-ntp01 | net-ntp01.uchicago.edu | 128.135.105.98 | TBD | 123 |
| net-ntp02 | net-ntp02.uchicago.edu | 128.135.105.116 | TBD | 123 |
The NTP Service is restricted to UChicago-owned IP space only. This means that any host connected to the UChicago wired or wireless networks will be able to synchronize with this service. Devices on home, open-public, cellular, or other networks will fail to synchronize and accurate time may be affected.
As time and NTP are sensitive to distance, devices located outside of the Chicago area should consider using globally open NTP services or servers much closer geographically.
In recent years, NTP has been a vector for causing network disruptions through carefully crafted packets. The Campus NTP Service has been configured to minimize or eliminate this threat. While discouraged, if you are operating your own NTP server, please review the article NTP Server Security Best Practices to ensure your server is configured securely.
Transient devices come configured to use a globally open NTP service by the manufacturer, for example, time.apple.com, and no extra configuration is needed. However, if you are manually configuring NTP on these types of devices, and the devices are expected to be used primarily off the campus network, please consider using one of the globally available NTP pool addresses.