I can give ou the main page for portforward.com & I suspect the differences between forwarding a port between the models is not dramatic. I'd guess they'll be similar. May I suggest you look thru the Linksys models (at bottom of page) & choose the one that is most similar to your modem softw. Use Port 6346 You will also need to follow the instructions on setting up a static ip.

After doing that, force ip within LW: Force ip instructions & sample image

After doing the above things you should find you'll connect much moe easily. Run LW for at least an hour to give it a chnce to connect properly 1st time around. Then check things by dong a test: Bug Report instructions & sample image & hopefullly your result will be true. Particulrly if you share files.