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Network Time Protocol (NTP)

Overview

Network Time Protocol (NTP) is a networking protocol used to help accurately keep time on a computer. Stanford provides several stratum-1 NTP servers in a load-balanced configuration for use by systems on the Stanford campus network. The servers are geographically dispersed on campus with one server off-site, each connected directly to a GPS antenna. 

Features

  • Maintains highly accurate time over the Internet
  • Compatible with all major modern operating systems such as Windows, OS X, Linux, and UNIX
  • NTP clients use historical data to accurately estimate time when time servers are unavailable
  • Uses the Coordinated Universal Time (UTC) time standard

Get started

To make use of Stanford's NTP servers for your on-campus system/server, configure your NTP client with the following load balanced name (the IP addresses for this pool of servers may change in the future):

time.stanford.edu

Note: These NTP servers are only available on the Stanford campus network, not from external sources.

Advanced configuration

Three Stanford NTP servers are available individually as:

  • time-a.stanford.edu
  • time-b.stanford.edu
  • time-c.stanford.edu

Note: These NTP servers are only available on the Stanford campus network, not from external sources.

In addition to configuring the NTP server, you may want to configure your NTP client to restrict to the following networks.  The following are the configuration lines used for ntp.conf on Linux/UNIX using the Stanford NTP servers.

  • restrict 171.64.7.0 mask 255.255.255.0 nomodify
  • restrict 204.63.224.70 nomodify
Last modified April 21, 2017