Configuring Clients

Apple macOS (OS X)

  1. Open System Preferences.
  2. Choose the "Date & Time" panel.
  3. Click the lock to make changes.
  4. Enter your password.
  5. Select "Date & Time".
  6. In the box next to "Set date and time automatically", enter

Cisco IOS and NX-OS

router# config t
Enter configuration commands, one per line.  End with CNTL/Z.
router(config)# no ntp server
router(config)# ntp server
router(config)# ntp server
router(config)# ntp server
router(config)# ntp server
router(config)# copy running-config startup-config

Google Compute Engine

Although you can use Google Public NTP from Compute Engine, you will get better performance from the private cloud servers, which serve the same time using the same smear. Follow these instructions.

Juniper Junos

NTP is configured at the [edit system ntp] hierarchy level:

system {
    ntp {


ntpd or chrony

  1. Edit /etc/ntp.conf or /etc/chrony/chrony.conf (depending on the service you're using) using your favorite text editor.
  2. Remove or comment out any lines starting with server, to prevent your machine from trying to mix smeared and non-smeared servers.
  3. Add the lines:

    server iburst
    server iburst
    server iburst
    server iburst
  4. Restart the NTP/chrony daemon using sudo service ntp reload or sudo service chrony force-reload.


  1. Edit /etc/systemd/timesyncd.conf
  2. Set the content of the [Time] block to:


    Leaving NTP= uncommented and assigned to an empty string resets the list of NTP servers, including any per-interface assignments. This prevents inadvertently moving between smeared and un-smeared time servers. Configuring Google Public NTP as the fallback server will cause it to be selected as the only NTP server.

  3. Restart systemd-timesyncd using systemctl restart systemd-timesyncd.service as a user with appropriate permissions

  4. Verify that your system is using Google Public NTP with timedatectl show-timesync | grep ServerName. If successfully configured, the output will show:

Microsoft Windows

  1. Open the Control Panel.
  2. Click the "Date and Time" icon.
  3. Choose the "Internet Time" tab. (This will not be available if your PC is part of a domain. In that case, it will synchronize time with the domain controller. You can configure the controller to use Google Public NTP.)
  4. Click the "Change settings..." button.
  5. Check the box "Synchronize with an Internet time server".
  6. Next to "Server:", enter

Microsoft Windows Server

Follow Microsoft's instructions to update your registry.