I have never used TCP/IP play with this game.  The game is bested played using a hosting website:  See 
www.pbw.cc.  PBW will run all the turns and destribute them when the Last player uploads his turn. Unless you are playing a tiny universe, it is not practicle to play the game in one session. Large empires can take up to an hour to run a turn (depending on your level of micromanagement).