Ok so since you are already planning on connecting via remote Composer, that opens up a vpn connection for you. I’m assuming you have putty already installed if you’re a C4 installer. Then in putty start a session to the controller running director via its public IP address on port 22. Now you’re in the network. From putty run something like this:

for /L %i in (0,1,255) do ping -n 1 -w 250 192.168.1.%i>>ipaddress.txt

(Replace the 192.168.1. With your network).

I am on a plane and going from memory on the script but you’re a smart guy...make it happen :-)