When you really did what you described it cannot work but maybe you just skipped a step in your description.
To be sure I describe the steps:
How to connect manually:
On server: go to lan game menu and press "host game". Now you should see a game setup with at least one slot open ( control is network )
On client type in the ip of the server and press connect. Now Client should see the same setup as the server...
How to connect via "find server" ( which was buggy on newer linux versions ):
On server: go to lan game menu and press "host game". Now you should see a game setup with at least one slot open ( control is network )
On client press "find LAN game". Now Client should see the same setup as the server...
