Testing FireNet connectivity Without Deploying Firewall Instance
You can test connectivity without deploying any firewall instances. When the FireNet gateway has no firewall instance attached to it for the data path, the FireNet gateway loops the received packet and forwards it to its destination.
You must first complete all FireNet workflow steps.
If you have an instance in one VPC/VNet/Domain and another instance in a different VPC/VNet/Domain, and you specify a connection policy between the Domains, you should be able to ping the two instances.