Hello
I just updated the firmware on my td-w8968 and that option has appeared in the forwarding section.
On my old router I had to forward my web cams to different ports or it did not connect, but with the w8968 it did not seem to matter you could forward to the same port and it worked ok.
But you can change the ports now.
Good luck

Forget the forsaking at the top the ipad keeps correcting my spelling

I don't know graphic interface from W8961ND, so give a screenshot from your configuration. We'll see those settings.