The following diagram lays out an example setup. It has a central Resource Manager server in the 10.10.10.0/24 network. The network local to the server is considered the default network within the system. The default network is treated exactly the same as a Resource Manager system without this ZenPack installed.
There are two other networks shown (r1 and r2) which are behind a firewall and have the same IP space 192.168.0.0/24. Each realm has a distributed collector located within it. The collector can be accessed from the Resource Manager server using a IP translation from the firewall to map the address accessible from in front of the firewall to an address behind the firewall. Remote collectors in a multi-realm setup must be accessible from the central server using SSH.