After you set the date and time on a device, you can synchronize the local time on a device with a Network Time Protocol (NTP) server.
The date and time are configured in the Exec mode and only have to be configured once per device because the value is written to nonvolatile memory. After the basic time information is set up, an NTP server is configured to allow the local time to be synchronized across the network.
ntp enable
no ntp enable
ntp peer [ ip address | domain name ]
no ntp peer [ address | domain name ]
ntp server [ address | domain name ]
no ntp server [ address | domain name ]