A virtual private network (VPN) gives you online privacy and anonymity by creating a private network from a public internet connection.
In other words, you are creating a gateway with a real IP Address. This gateway creates a simulated network for all devices connected to it. Devices would experience each other through the network in the same fashion as if they were in the same home.
OpenVPN is by far the simplest solution to create your own VPN server. However the use of a VPN server may require someone who is tech-savvy to install and manage it.
If you don't know how to already use a VPN then this option is probably not right for you.
Things to Note
See updated information here /configure/p2p
"A port forward is a way of making a computer on your home or business network accessible to computers on the internet, even though they are behind a router." - portforward.com
Similar to VPN this will require a tech-savvy user. This is also the worst option you could choose because it allows direct access to your server. Depending on the router you may not be able to secure it very well either. Depending on the Internet Service Provider your Shinobi is connected under you may not be able to use this option at all.