On the Time Setting page, you can set the time zone for a host and add or remove the NTP server(s) that the host uses to synchronize time. If you set a time zone, you will be able to set up a maintenance window through the Cloud Services Portal.
To add a new NTP server, click Add; to remove one, select the checkbox for it and click Remove. When you add and use a new NTP server, the host will use it and will not retain the default settings.
If you select the Sync with ESXi checkbox for hosts deployed through OVA on ESXi servers, the list of NTP servers on the Time Settings page will not be used for the host. To have such hosts synchronized with an NTP server, enable the Synchronize guest time with host option during the deployment. If you do not select this option (or if it is disabled) during the deployment, the host will synchronize with the Ubuntu NTP servers ntp.ubuntu.com and ubuntu.pool.ntp.org. If you disable the option during the deployment and select the Sync with ESXi checkbox, be sure to open the UDP 123 port, to have time synchronized with the Ubuntu NTP servers.
Click Next to go to the Proxy Settings page. You can also click Cancel to cancel the configuration or click Finish to save it.