You need to set up DC++ properly.
1) Open DC++, and open the settings window. In the "Connection Type", enter the port that you want DC++ to run on. Choose 1412. Go the www.whatismyip.com
, and enter that IP address. Click OK.
2) Open your firewall settings. Click Settings - Administration - Security Level and Firewall. You will need to enter your root password when prompted. In the window that is displayed, click "Other Ports", and then click Add. In the small window that comes up, enter 1412 for the port number, and click OK.
3) You have not said if you are behind a router yet. If you are, you will need to set up a "Virtual Server" on that router, forwarding port 1412 to your computer.
I hope this helps