When setting a new primary DNS server in the Cisco UCM CLI, what is required for the change to take effect?

Restarting the CallManager service only affects call processing functions and does not re-initialize the underlying network-level DNS configuration.

Restarting the DirSync service is specific to directory synchronization processes and has no impact on applying new DNS server settings for the node itself.

Changing fundamental network configurations like the primary DNS server on a Cisco UCM node through the Command Line Interface (CLI) necessitates a full system reboot of that node. This ensures that the operating system and all dependent services correctly adopt and initialize the new DNS settings, which are crucial for network communication and service resolution.

Restarting the TFTP service is for phone configuration file distribution and does not apply new DNS settings at the operating system level for the CUCM node.