Which preliminary step should be taken before data is forwarded to an indexer or search head?

The correct preliminary step before data is forwarded to an indexer or search head is to configure receiving on the indexer or search head. This is essential because configuring the receiving end ensures that the system is set up to accept incoming data from the forwarder. Without this configuration, the forwarder would not know where to send the data, and the indexer or search head would not be prepared to receive any incoming logs or data streams.

When receiving is properly configured on the indexer or search head, it allows for specific data inputs, ports, and listener settings to be defined. This setup is crucial to ensure that Splunk can effectively process and index the data as it arrives.

The other actions listed pertain to steps involved in the overall data forwarding process but occur after the receiving configuration is established. For instance, installing a forwarder is necessary to get the forwarder onto the source machine, and starting the forwarder is required for it to begin sending data. Configuring the forwarder to collect and send data is also critical, but it relies on having the receiving end already set up to ensure successful communication and data transfer.