Go to server op forum. In the top stickied posts, you'll read "How to set up an NS Lan server"
Better yet, I'm so nice of a guy, I'll even link ya: <a href='http://www.unknownworlds.com/forums/index.php?act=ST&f=8&t=40285' target='_blank'>http://www.unknownworlds.com/forums/in...=ST&f=8&t=40285</a>
Edit: Your client version comes with the server version installed with it, too.
Comments
Better yet, I'm so nice of a guy, I'll even link ya:
<a href='http://www.unknownworlds.com/forums/index.php?act=ST&f=8&t=40285' target='_blank'>http://www.unknownworlds.com/forums/in...=ST&f=8&t=40285</a>
Edit: Your client version comes with the server version installed with it, too.