Hi Chewbaccah, welcome to the forums!
What OS are you using to play Outpost 2 with?
With NetHelper enabled and playing version 1.4.0 you may be able to start a multiplayer game without hamachi. I had to use hamachi myself though.
I have played a couple of times recently using OP2 1.4.0 with Hamachi with great success on Windows 10. NetHelper is supposed to support hamachi out of the box, but we had to disable NetHelper to get it to work. If you are trying to use Hamachi with NetHelper enabled, I think Outpost 2 will still show you your external IP address and not the Hamachi assigned one.
If you cannot get it to work with NetHelper or NetHelper+Hamachi, try the following:
1. Close Outpost 2
2. Go into Outpost2.ini and set NetHelper=no (look under the section header ExternalModules)
3. Set Hamachi to the highest adapter setting Network Status -> Change Adapter Options -> Right Click on Hamachi -> Internet Protocol Version 4 (TCP/IPv4) -> Properties -> Advanced -> Clear Automatic Metric
4. Set the Interface Metric to 1 (lower number means higher priority)
4. Startup Outpost 2 and your Hamachi assigned IP address should show up when running a TCP/IP game
Good Luck and let us know how it goes. I think Discord is the best place these days to find others to play with.