Let DC++ autoconfigure the Internet connection

If you are behind a router that supports uPNP:

• Make sure the uPNP feature is active in your router. Usually is disabled by default.
• First you need to enable UPnP in Windows. 
• Make sure of this by checking the “Universal Plug and Play Device Host” and “SSDP
  Discovery” services. Both of these services should be set to
  “Automatic” startup and “Started” status.
• In DC++ activate the “Firewall with UPnP / Use UPnP to let DC++ configure my router” 

Check if your port is open at www.portforward.com

Enjoy.