Use a routable IP address. Not loopback. Access it remotely like a normal IP application.
For security, firewalls with default deny of TCP and UDP are a good idea, as usual. Allow rules for this could be restricted to smaller nets in some internal zone. Firewall rules can open a large range of ports, if that is needed. All ports is extraordinary, if I were firewall administrator I'd ask for you to restrict to a smaller range.
Depending on what this application is and what networks it needs to traverse, you may wish to tunnel or proxy in some way. Or leave it as localhost only, and require remoting into this host (such as with ssh) to access the thing running on its loopback.