CAUSE
When Grid members are behind a firewall, reports may not get through to the reporting server (indexer) if the firewall rules are not configured to allow the required ports.
By default, grid members use TCP port 9997 to forward reports to the indexer. The communication between the forwarder and the indexer uses SSL and is compressed, which is not changeable. If the forwarder has multiple interfaces, system administrators have no control over which interface sends the reports. By default, the indexer listens on all its interfaces.
RESOLUTION
To ensure that the indexer can receive reports, verify that the configured TCP port is open for communication between the forwarder and the indexer and that the forwarder's interfaces and the indexer's interfaces can communicate over the configured TCP port. By default, the configured TCP report is port 9997.