Hi, can't answer your question directly, my network skills are to low.. but, you should start by upgrading your router with the last Kong build, with updated drivers, much better wifi performance, and new bug fixes
I did a 30/30/30 reset on my WRT1900ACS and then installed the latest Kong build (25 March 2016) for the WRT1900ACS. After setting the router up again, I'm getting the same results. A couple of my devices with port forwarding and UPnP work and can be accessed from the WAN, and the rest don't work.
I unplugged the WRT1900ACS and replaced it with the old Netgear R7000 (stock firmware) and all of the port forwarding works again.
Any suggestions? I don't think it's the firmware, am I missing something in my setup?
After troubleshooting, port forwarding is working only if the external port is the same as the internal port. If I assign a different external port, it fails. Did I miss something? What do I do if internal port is 80?
UPnP still not fully working, about 33% success rate. Not sure what the failed devices have in common yet.