A Network Time Protocol (NTP) server is used to obtain the correct time from an external time source and adjust the local time in each connected device. When the NTP server functionality is enabled, the NTP server starts listening on the NTP port for client requests and responds with the reference time. Up to eight server addresses in IPv4 or IPv6 format can be configured. When you configure multiple NTP server addresses, the first obtainable address is set as the active NTP server. If there are no reachable time servers, then local device time is the default time until a new active time server is configured.
The NTP server is stateless and does not maintain any NTP client information. Network time synchronization is guaranteed only when a common external time server is used by all devices.