NAT type D on Nintendo Switch using XR300

[jakecantsay]

g'day

I've been using an XR300 gaming router for 2.5 years now, with no issue for the first 2 years or so. Then recently I tried playing some Nintendo Switch Online and noticed I could not join a lobby in any games. A connection test on the Switch told me I have NAT type D, I know for a fact it used to be B up until this point.

I have not touched anything since setting the router up and connecting my devices. 

I've tried port forwarding, UPnP on/off, DMZ server, firmware updates, factory reset, wi-fi and ethernet connections, everything. No luck

I know it's the router because I get NAT type B on the wi-fi at my parents house and on my phone hotspot. The NAT type on my Xbox Series X is 'Open' so this is a unique issue with the Switch.

The Nintendo website recommends forwarding ports 1024 - 65535, however the port forwarding menu in the DumaOS interface only allows you to go from 1 - 65534. Is this elusive 65535th port the problem? 

Any help would be greatly appreciated!

XR300 Router

Firmware version: 1.0.3.78_10.3.59

[jakecantsay · Accepted solution]

Thanks for the reply.

I had also tried this as part of my troubleshooting (forgot to list it). No dice


I ended up finding a post on the Aussie Broadband subreddit (https://www.reddit.com/r/AussieBroadband/comments/zvi5w8/nintendo_switch_nat_type_d_issue_help_pleas...) where someone suggested that it was the ISP enabling CGNAT. I called them to opt out of that and it resolved the issue.

[Netduma-Fraser]

In WAN Settings set NAT to Open, then check the console and see if you get a better NAT result. It won't be that last port causing the issue.

[jakecantsay · Accepted solution]

Thanks for the reply.

I had also tried this as part of my troubleshooting (forgot to list it). No dice


I ended up finding a post on the Aussie Broadband subreddit (https://www.reddit.com/r/AussieBroadband/comments/zvi5w8/nintendo_switch_nat_type_d_issue_help_pleas...) where someone suggested that it was the ISP enabling CGNAT. I called them to opt out of that and it resolved the issue.

[Netduma-Fraser]

Brilliant to hear that and thanks for posting your solution!