Good afternoon Alex. I would not reccomend using a 1:1 Nat as it could expose (and probably will) your xbox to the entire internet. If you are getting a Strict NAT type this tells me that your firewall is probably behind a NAT OR your ISP is also NAT'ting your internet connection. A quick check for when I run into this is to see what the actual IP address is you are getting on your firewall. If you check the uplink tab under appliance status. you should see "public IP" in grey with what Meraki sees as your public IP. If that IP is not the same as your WAN 1 confgured IP then likely your device is behind a router or something is Natting your device upstream. Often with home users your ISP provides a local network (192.168.x.x 172.16-32.x.x or 10.x.x.x). If that is the case you would want to work with them to get your router configured in pass through mode so that your MX pulls a public IP rather than a private.
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