I am using an old laptop running TrueNAS core to run my MineOS version, with a completely stock installation. The server works fine on the LAN, but when a friend tries to connect it does not work. I have tried obtaining a static IP address, but that did not seem to help. If anyone has any ideas as to why this server is not working, I would love to hear them. If there is any other information that you need, just ask. Thanks!
Most likely you need to set up port forwarding between your internet IP and your LAN due to NAT.
take a look at this page and see if they have a how-to for your internet router:
To find your internet IP use the following link: