NAT constantly goes from open to strict on Xbox One
 

Telus PureFibre 150
ActionTec T3200M
Wifi (but I have the same issue when I go wired as well)

-Followed this tutorial for setting up a static IP + opening the proper ports for optimal xbox one online gameplay
-For the static IP I went into the advanced settings on the router/modem, DHCP Reservation, and set it up as in the tutorial.
-I opened up all my ports followed by putting the static IP used for my xbox on DMZ mode.

After I do all of the above I get an open nat and everything runs great.. for a few days at most. Eventually it just says strict once again. The only way I can get it back to being open again is by removing all the ports, dmz, static ip settings, rebooting the modem/router, and then redoing everything. The exact message that I get on xbox when it turns back to being strict is: "Your network is behind a port-symmetric NAT".

Any ideas?


More...