Well although the Belkin F5D7230-4 is supposed to be able to utilise UPnP (Universal Plug and Play), it apparently doesn't work. This can be seen from this article
HERE (click on link.) Thus I would think you may require forwarding (opening) a port.
Forwarding a port for LW requires 3 steps. The 1st step is arguably the most important b/c otherwise it won't work properly. You 1st need to set up a Static ip.
1. Set up a static ip.
2. Forward port 6346 using
Guides for the Belkin F5D7230-4 (instructions for setting up a static ip are included.) And find Limewire on the list when you get to the port forwarding.
3. Within LW:
Manual port forward instructions & sample image & 2 posts after that.