Like others on here i've just recently had a strict NAT come slamming down. I've port forwarded, DMZ'd, turned off firewall, enabled plug and play, given static and DHCP addresses etc etc etc. None of it has worked. Went through the xbox website however and found out that apparently a public ip address is needed to eliminate the NAT issues (i'm not inclined to believe this).
It's getting pretty frustrating that after spending a large sum of money a month and owning a very expensive console that this doesn't just work out of the box. Online gaming had been around for a VERY long time and stupidly popular in the last 8-10 so why is this STILL an issue?
Change your power mode to Energy Saving from Instant-on.
Offline System Update Diagnostic Tool on Xbox One: http://bit.ly/1e8bSs3 Network ports used by Xbox Live on Xbox One: http://bit.ly/1dCNLm0 xBox Support: http://bit.ly/1lE2QrK Xbox One operating system versions and system updates: http://bit.ly/1NiJS1j
Thanks for getting in touch, appreciate that strict NAT can be a pain, though looks like you've covered most of the options to try and lift this.
I've run a few checks on your connection from this end and all looks in good shape, with no obvious issues to explain any performance problems over the past few days.
If the strict NAT issues are still ongoing it may be an idea to try a quick factory reset of the Hub via the pinhole on the back if you haven't done so already or trying the SuperHub in modem mode to see if this helps.