Network Time Protocol (NTP) server provides the correct network time on the device. NTP can be used to synchronize the time on devices across a network.
Network Time Protocol server is used to obtain the correct time from an external time source and adjust the local time in each connected device. When 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 five server addresses in IPv4 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.
When synchronization is lost, NTP server operates in master mode to serve time using the local clock. Serving local clock can be enabled using the NTP master command.
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.