@pccheese , your first problem is using Ubuntu 17.04 ;-)
That may be way too bleeding edge for what you are trying to do.
16.04 is LTS, meaning mainstream support for the next 3.5 years, where is 17.04 is experimental and abandoned after a year or two.
Anywho, before I hear it from @nick, to each their own is my retort.
Your problem is you need to either use the Gui to create an Internet connection share, or if you really want to do it via Terminal, you need to use IP tables to forward packets from one Interface to another.
This page may help.
https://help.ubuntu.com/community/Internet/ConnectionSharing