What command do we use to tell a deployment client where to phone home?

The command to tell a deployment client where to phone home is "splunk set deploy-poll SERVER:PORT." This command sets the configuration that specifies the deployment server's location, enabling the deployment client to connect to it for updates and configuration information.

When using this command, the CLIENT identifies the deployment server by specifying the server's address and port number. This is essential for deployment clients so that they can pull the necessary apps and configurations from the designated deployment server, ensuring that all clients are up to date with the correct settings and applications.

The other choices do not serve this specific function. For example, "splunk configure deploy-poll SERVER:PORT" and "splunk config deploy-poll SERVER:PORT" are not valid commands in the context of setting the deployment server. The distinction lies in the syntax and the specific command intended for configuration purposes. The "splunk set deploy-client SERVER:PORT" is not applicable because it refers to a different setting related to defining a forwarder's role rather than specifying the deployment server for the deployment client.