Open a command shell when you are online and type netstat -av, and look for the port 27374 to be open, if you have subseven this is the default port that will be open, look for any port numbers that are out of the ordinary. Actually, if the firewall is any good it probably logged the connection attempt and it will have the port number that someone tried to connect to. You might try setting your firewall to a learning mode where it asks you which taffic can go out and which can come in. More than likely everyone is right, it was just a scan. Hope this helps.
-libertie