Enter this into your browser address bar: http://192.168.1.1
Enter user and password. Default should be '1234' (both for user and psw) or 'user'.
Go to Advanced setup -> NAT
You will see this text:
NAT -- Virtual Servers Setup
Virtual Server allows you to direct incoming traffic from WAN side (identified by Protocol and External port) to the Internal server with private IP address on the LAN side. The Internal port is required only if the external port needs to be converted to a different port number used by the server on the LAN side. A maximum 32 entries can be configured.
Press 'Add' and enter the following data:
- Use Interface: eth0.3
- Service name (custom): DC++
- Server IP Address: 192.168.1.xx (where xx is you computer's internal IP address. Type 'IPCONFIG' in a DOS box to find out your IP).
- External port start: 7777
- External port end: 7777
- Protocol: TCP/UDP
Do all this stuff one more time for the 9999 port.
Now you can apply/save the settings.
In DC++ enter the 7777 port in the 'Transfer port' field and 9999 in the 'Search port' field. Activate the 'Active mode (I have configured my router)' option.
Note: There is a better option: in your router config panel, go to 'Advanced -> UPnp' and check the 'Enable or disable Upnp protocol' box. This will allow DC++ to directly interact with your router and configure it.