About Double NAT

[CrimpOn]

When a router (Orbi) is connected directly to another router (ISP device), the Doublt NAT condition interferes with a number of applications, such as Port Forwarding, VPN, some types of streaming services and some types of internet gaming.  Unless a user is using one of those applications, they can have a double (or triple) NAT and never notice it.  I am convinced that thousands of customers do exactly that. Just plug in their new WiFi router (any brand, not just Orbi), use the SSID/password printed on the label, and "off they go."  It is only when a user has one of those specific needs that Double NAT becomes an issue.

We usually advise that the user choose one of two solutions:

• Put the ISP router into bridge mode so that the Orbi is the only router and all of these applications can be facilitated using features on the Orbi, or
• Put the Orbi into Access Point (AP) mode and use the ISP router features to facilitate these needs.

There is third alternative: Use features on both routers.  As an experiment, I set up a router connected to my Orbi and attached a computer with an SSH server to this second router.  Forwarded port 22 to that computer.  On the primary Orbi router, I forwarded port 22 to this new router.  So the sequence is:

Public IP-> Orbi. Port 22 forwarded to 192.168.1.93 (new router).  Port 22 forwarded to 10.0.0.2 (computer).

Opened smartphone Hot Spot and connected laptop to the internet (bypassing Orbi and ISP).  Opening an SSH connection to my Public IP connects directly to the computer. Through the "Double NAT" of two routers.  Works fine. Could use the same technique to expose a web server, a security camera, an FTP server... the list is endless.  The downside is that every step has to be done twice: once on the ISP router and once on the Orbi.

We recommend two solutions because once done, they remove Double NAT from every situation.  Suppose a person has a situation where they cannot put the ISP device into bridge mode and do not want to put the Orbi into AP mode?  For at least some situations, option three may be a solution for them.

[FURRYe38]

Also gaming configurations can be effected by double NAT conditions which is not preferred.

• A 4th suggestion would be to use the 1st routers DMZ or IP-pass through feature for the 2nd router as well to help with double NAT problems seen in these certain senarios. This is the most easiest method IMO.  

[bariumslinger]

So I have a situation somewhat related and need help. I have a Netgear MR5100 5G modem running on the ATT network and connected to that is my Orbi router (850) plus 2 satellites. I set up the modem with IP passthrough ON, DHCP OFF, ethernet standby disabled, and usb-c as charge only. I am running into NAT 3 limitations on my PS5 and am wondering if setting up the OpenVPN within the orbi will allow me to fix my NAT problem. I've never dealt with NAT issues before, so forgive my noob status.

[CrimpOn]

OpenVPN is not likely to have any effect on the PlayStation 5 situation.

According to this article, the solution is to use Port Forwarding rules on the Orbi router:

https://www.androidcentral.com/how-to-change-nat-type-ps5 

[bariumslinger]

Yeah, I tried that. Also tried DMZ. Also tried changing NAT from "secured" to "open" in the Orbi advanced settings. No change, still strict NAT. I think the problem is the ATT modem. Frustrating. I will scour that article and see if there is something I didn't do correctly.

[CrimpOn]

One quick test is to verify that the Orbi has a 'public' IP address.  On the Advanced Tab Home Screen, the box Internet Port should show a public IP address, rather than a private IP address.

[FURRYe38]

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

Do you use DMZ or IPPassthru ON the ISP modem for the RBR? 

For any Orbi AX help and information, Netgear has set up a community forum specifically for the Orbi AX (WiFi 6) products. Most of the people who watch that forum are more likely to have experience with Orbi AX and know how to work it better than those of us who follow this "general Orbi" forum. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/Orbi-AX/bd-p/en-home-orbi-ax

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you

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@bariumslinger wrote:

Yeah, I tried that. Also tried DMZ. Also tried changing NAT from "secured" to "open" in the Orbi advanced settings. No change, still strict NAT. I think the problem is the ATT modem. Frustrating. I will scour that article and see if there is something I didn't do correctly.

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