RFGrinch

I've given you Early Access so you can try the firmware there: https://forum.netduma.com/forum/151-netduma-r3-early-access/
Regarding your NAT, it could be CG-NAT, could you run this test and let us know the results please? https://support.netduma.com/docs/dumaos-3/open-nat/#cg-nat

Well thats all done. Will have to check back in later on or tomoz. See if double and strict comes back. Never ending

I will try something with their tech team. I know it isnt meant to act like this clearly. Drives me mad lol. I will let you know what i find out. 

Double NAT only occurs when you have two routers in play and one isn't passing through all the traffic to the other so it will be something to do with the static IP/DMZ not being valid anymore for some reason, check all that in case any of it has changed

I will have to try everything tomorrow. I will boot everything up and check all settings as fraser mentioned. After that i will post and go from there. May just get my own static ordered and should fix the issue forever. No more back and forth. Would rather not spend even more money each month on it. But we shall see

Try unplugging his console then reset your router and your Xbox and see if u get a open nat 

I get you but it’s still connected to your network even in standby. try totally disconnected the power then see if that makes a difference

I see. Are you able to use your R3 as your main router?

So from what I can remember from reading this thread is that you are using your isp router and you have connected a R3 through Ethernet and now you have a temperamental NAT Type.
 
I would say if possible connect your routers the other way around use the R3 as a main and connect the other through Ethernet and still connect your nodes to the router it’s currently connect to.
If that’s not possible then you should go into your main router and change your dhcp range shorten it to reserve a static ip address for the default gateway of the R3 eg( ip range 192.168.77.1 - 192.168.77.250)
login to the R3 assign a ip address that is out of the range of what you put in your main router eg (192.168.77.251)
disable the dhcp on the R3 and assign your Xbox a ip address with your main router and also put that same ip address of your Xbox into the DMZ of your main router and if that don’t work try both routers.
I know this was a bit long winded but I hope you was able to keep up and understood what I was trying to explain please try any of these method’s and let me know got you get on and let me know if you need further help. 
 
Monsta
 
 

Your DMZ is not enabled 
put your x box ip in for source and destination and try that 

Righty. Well i did all that. Restarted everything. Its now open on xbox. Thanks guys. 
ipv6. U say i should disable that on R3 til u guys fix it. 

Yes that's correct

It's the DHCP reservations button that you want from the first image

That doesnt look like the page you want. You need to find a page that has DMZ on it. 

Exactly as above - looks like the screenshot you provided was for Internet Settings which you don't want to change. Could also be in LAN Settings.

In your ISP router, you will need to give the R3 a static IP. You might find this in DHCP page. Once you set this static IP, you then need to put that IP into the DMZ page and enable it. 

It's purpose isn't to beat SBMM but to give you a better gaming experience so if that is your goal then there is no guarantee that would work. For Xbox parties you'd just need to add friends on the Geo-Filter allow list.

Have you got the R3 in the DMZ on the Sky Hub? You will need to do that to eliminate the double NAT

Copy the R3 WAN IP from Settings > WAN then access the Sky Hub interface and paste the IP into its DMZ function

Great to hear that, thanks for the update!

Removed double nat and all is open now. Huge help  
Thanks bud. 
 

Thanks a bunch. Will do this in a short while. Have a fab weekend. 

Thanks bud. I will check this out. Have a tinker about. 

This must be due to UPnP not automatically opening the port for NAT quickly enough after starting the Xbox. You just have to test it for it to be operational... (power saving mode maybe)

Thanking you. I know it works just fine. Its just something ive noticed thats missing for some reason, and dont have a clue why it puts me at double nat and moderate every time.