Others cannot access my game

[symphonia117]

when my friends try to access my game they cannot (i think it is ip address thing) he says the server is offline from his house when i can access the game from mine (server is on) I never changed ip address like guide told me to because i was able to access my game, and also because i do noy know how to find my ip address. can anybody help me?? please… oh and also. when he got the cliant from my site with all the maps and crap, on the config page he said he could see my pass and user name and he said they had already been entered inot the log-in screen.HELP!!! ME!!!!