Since you cannot change the firewall, can you change the location you run the script? You said that when you ran it as a proof of concept on your PC (on the same side of the firewall as the Exchange server) it worked but that you did not want to run production code on your PC. Is there a production grade PC behind the firewall that you can run it on? That would solve your problem
Yes, and no. Sure I can successfully run this from another host, but eventually, I'll be looking at the database that is local to the FTP server. Makes sense to run this from the FTP as well, but may not be possible.