- 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"