This is a tutorial showing you how to play "Blue Sun" over the internet. It will probably be out of date once the new version comes out (I will be replacing current multiplayer functionality) but I am not expecting to release anything anytime soon.

1. Forwarding ports.
All players that wish to play "Blue Sun" over the internet and are using firewall or a router, must unlock certain ports.
You dont have to do this to play on a local network (LAN) or if you are not using firewall/router.

Please keep in mind you are forwarding the ports on your own risk.
If you are not sure what youre doing please look around the internet and learn more about port forwarding first.

I will not explain how to forward ports here because it depends on the hardware and software you are using.
I can only direct you to this site. It explains how to forward your ports.
You must select there, the router you are using and then a program which you want to unlock ports for.
You wont find "Blue Sun" on the list with programs but you can choose something else (e.g. "Homeworld Cataclysm").
The guide will tell you to unlock specific ports for the program you chose. Instead of those mentioned there, for "Blue Sun" you will need to unlock following ports:

• From 2300 to 2400 (TCP)
• 47626 (TCP)

2. Hosting a game session.
Run "Blue Sun" and in the main menu pick the "Multiplayer" option. Then click "Host Game Session".
A window will appear letting you enter your player name, session name, and optionally a password.

If you are wishing to play over the internet you must check your IP address.
You can do it for example here. Tell your IP address to the person youd like to play with.
If you are playing over a local network (LAN) then you dont need to check your IP.

3. Joining a game session.
The person who wishes to join the hosted game session must launch his/her game.
When the menu appears click "Multiplayer" button and then "Join Game Session". In the window that appears you must enter the IP address of the hosting computer.
If you are playing over a local network (LAN) then you dont have to enter any IP. Just leave the text field empty and click "Continue".

If all goes well you should be asked for your player name.
If the game host chose a session password you will also be asked to enter it.
Finally you should see a game setting menu. The host can then set up the game and start the match.

Problems
Unfortunately currently "Blue Sun" uses multiplayer communication method which is very troublesome.
Not only all players behind a router/firewall must unlock their ports what is bothersome, but also connecting sometimes seems impossible.
I did managed to launch the game over the internet after setting up my ports, but there were also people which I couldnt connect to.
Playing the game over the internet probably wont work easily, if at all but you can still try it.
I havent tested it but I think people without routers/firewalls should be able to play without problems or port forwarding.
You can also play the game over local network (LAN) as it also shouldnt cause any problems.
I will be replacing whole multiplayer communication mechanism as soon as I can, to make it less troublesome and more user friendly.

I have recently join this site and Nice idea for providing us information about Multiplayer game. Would you mind to let us know more about this? Thanks!

Well as I have mentioned this multiplayer system will be replaced in next version. (It actually already is but I still need to work out some issues before release.)

Still if you need help using the old system then just ask. What exactly do you need to know?