You may be running a firewall which may prevent communication between the cluster hosts.
The preferred configuration is to set up a firewall at the perimeter of the cluster to restrict network access to the cluster hosts but not communication between the cluster hosts.
If you are running the product on a standalone host and do not intend to use this host in a multiple-host environment, you can ignore this message. If you are running the product in a multiple-host environment and your security plan requires a firewall on the host operating system or between hosts, see the firewall configuration guidelines in the product documentation.
