To ensure all devices receive the time from the local environment with the least administrative effort in a private cloud model, the organization needs to use the Network Time Protocol (NTP).
NTP uses port 123, so the organization needs to open port 123 to allow NTP traffic to flow through the network.
Port 53 is used for DNS traffic, port 67 is used for DHCP traffic, and port 161 is used for SNMP traffic, but they are not related to the time synchronization requirement.