Question: Mirroring requires the administrator to assign private IP addresses to the master and replicas. When the master communicates with the replicas, do these private IP addresses show in the network packets?
Answer: No. The communication between master and replicas are encapsulated and encrypted using IPSec tunneling. The packets with these private IP addresses go only through this IPSec tunnel and are not visible on the actual network where the search appliances are deployed.
Additional Details: For more details about the implication of mirroring configuration, please read About Security. There are certain network addresses which cannot be used for the private IP address.