What is NTP?

NTP is the Network Time Protocol, documented in RFC 1305. It allows systems to synchronize their clocks to high accuracy over the network.

NTP Support at Fermilab

The Data Com & Networks Group has four master network time servers with clocks set from GPS satellite signals. Most routers on site synchronize their clocks to these servers. The routers in turn broadcast NTP time updates to their directly-attached subnets.

NTP client applications should be configured in broadcastclient mode, allowing the NTP client application to "listen" for the NTP broadcast updates from the router. By default, the routers are configured to broadcast NTP V3 updates.

If the NTP client application does not support the broadcastclient mode (or NTP V3 broadcast updates), the client should be configured to setup a server association with each of the following 2 hub router interfaces : 131.225.8.200 and 131.225.17.200.

Questions regarding NTP client application configuration and/or NTP broadcast update problems should be directed to the Fermilab HelpDesk, who will forward the questions to the appropriate support people.

NTP Support from Off-site

NTP queries to the site NTP providing devices is restricted to local site networks only. In order to use these devices from off-site, you can install and configure the Fermilab VPN Service.

Otherwise, you can use the Public NTP Servers.

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Data Com & Networks