NTP Check

About NTP Checks

The NTP (Network Time Protocol) check requests a timestamp over UDP from your NTP server and waits for a reply.

When to use NTP Checks

Use our NTP check when you want to monitor the uptime of your NTP servers or to receive alerts when private servers become publically available, as in the case of a failing firewall rule. The check can be configured to send you notifications if it's able to get a response or if it's not able to get a response.

Using NTP Checks

To set up an NTP check,

  1. Select NTP from the Check type drop down.
  2. Give it a friendly label to identify this check in lists and notifications.
  3. Enable Automated Diagnostics if you'd like detailed technical info about the failure that may help you troubleshoot a failure.
  4. Set how often (in minutes) you want the check to run in the Check Frequency field.
  5. Enter the host where your NTP services are that you'd like to monitor. The fully qualified domain name or the ip address is required.
  6. Enter the port number the service is running on. The default is 123. This is required.
  7. Choose 'Pass if it responds' if the service should be publically available and you would like to receive alerts if the check is unable to get a response. Choose 'Pass if it does not respond' if your NTP service should not be available (it should be offline or blocked by a firewall) and you would like to receive alerts if the check is able to receive a response.
  8. Set a time out threshold in seconds. This is how long the check will wait for a reply. The default is 5 seconds. The maximum timeout is 10 seconds.
  9. Set the Sensitivity. The default 'High' is usually appropriate as it provides two immediate rechecks (three checks total) before declaring the check up or down. If the service often fails, you may want to lower the 'Sensitivity' to receive fewer notifications.
  10. Set the notifications for this check. More information about notifications.

Other considerations

Our NTP check doesn't currently support IPv6. This will be added soon.

If you have any questions, get in touch at, or use our Contact form.