Accurate timing on cameras and servers helps with numerous services, operation, and support. Most cameras and system provide ways of syncing the device/system time with a NTP server, whos sole purpose is for accurate time keeping. This can often be achieved by programming in the NTP server you wish to synchronize your system with. It is important for system licensing and support that the cameras and servers be synced.
If your network is allowed internet access, you can synchronize with the NIST Internet Time Service hosted by the National Institute of Standards and Technology. To reference with any of the NIST servers, you can use the nist.time.gov and your camera or system will sync with one of the servers in the NIST pool. If you wish to sync with one specific server, you can review the list of servers provided by NIST on their webpage, https://tf.nist.gov/tf-cgi/servers.cgi .
If your network is closed to the internet, you will need to have a time server on the local network to provide the sync reference. One such server is the Veracity TIMENET Pro™, https://www.veracityglobal.com/products/networked-video-integration-devices/timenet-pro.aspx, and uses GPS satellites to provide accurate time for local devices that synchronize with it.