I learned that Starbound is actually incredibly easy to make a server for? All I had to do was port forward and press a button labled launch Starbound server. My internet is kinda crap though, so the connection isn't great, but yeah I was at least able to play with a friend.
Also today I learned port forwarding is like incredibly easy, though like all the instructions I saw seem to be overly complicated.
All you have to do is go to your router, which for mine is router/.
Look at your options and find port forward

and then put in the port that it uses

EDIT: Also from what I understand Private IP address is really just your IPv4 address.
From what I've done (portforwarded a couple routers, both were a bitch to work with) your router has firmware specifically meant for port forwarding.