Plex insists I'm double NAT, but I only have 1 router and 1 modem

[Angrybob]

Server Version#: 1.42.1.10060
Player Version#: 1.42.1.10060

This is the Plex Media Server for the OS Sequoia. I’ve uploaded the server logs.

I would consider myself a tad bit more knowledgeable than a beginner.

I’ve done everything I can think of to try and resolve this. Under Remote Access, I click to enable Plex for outside my network. It stays Green for a bit, but clicking around quickly returns it to red. A common problem I’ve seen.

I think the issue could be Plex thinking this is a Double NAT issue. I only have a Router/Modem combo. Specifically, the AXE5400 Tri-Band Wi-Fi 6E Router, and NOTHING ELSE.

My iMac connects Wirelessly. I’m wondering if it thinks it’s Double Nat issue stems from what I see under the Wireless settings under my router. I see that there are 2 bands. 2.4GH/5GHz, and a 6GHz band. I’m wondering if these 2 bands are what are causing Plex to think there is a Double NAT issue.

If not, then I am at a loss as to what could be the cause.

I have tried port forwarding and there doesn’t seem to be a change. I have noticed that when I do “find my IP”, it has a different address than the IP address on my Mac.

I’ve checked my firewall settings and Plex is in there as an exception for Plex.

Another thing to add, though I’m not sure if it matters, I also have another program called Wimoweh. From what I understand, it just prevents Plex from sleeping.

Yeah, I’d be very grateful for any and all help. Again, I am a bit of a novice with this sort of thing, and I’m hoping this is an easy fix.

Thanks

<If providing server logs please do NOT turn on verbose logging, only debug logging should be enabled>

Plex Media Server Logs_2025-08-13_09-56-40.zip (3.7 MB)

[pshanew]

The cause for a double-NAT configuration doesn’t necessarily need to be your internal network topology. See Carrier-grade NAT - Wikipedia

The first thing I would check is what your router shows as your WAN (public) IP address. A dead giveaway that you’re in a CG-NAT config is if your public IP address in in the range 100.64.0.0/10. (Though it could be any RFC-1918 range as well.)

[BigWheel]

Look at the WAN/Public/External IP address in your router.

Looking at your logs I see it thinks that it is 192.168.5.10 which is a local address not from an ISP. this is why thinks on double nat

Aug 13, 2025 09:31:42.075 [0x16f763000] DEBUG - [Req#28d7] PublicAddressManager: got WAN IP 192.168.5.10 from router

Your servers local address is 192.168.0.80 which is a different subnet.

If you are on wifi make sure you are not on maybe a Guest network. but need to figure out where that 192.168.5.10 address is coming from.

[Angrybob]

Thank you both for the quick reply.

I checked the DHCP Client List and it seems my iMac is listed as 192.168.0.80. I noticed the difference there as well.

I don’t know how to tell the router to change it. Or what I would need to do with Plex about it.

As for a Guest Network, it shows as disabled.

For The first thing I would check is what your router shows as your WAN (public) IP address. A dead giveaway that you’re in a CG-NAT config is if your public IP address in in the range 100.64.0.0/10. (Though it could be any RFC-1918 range as well.)

Under the routing table, it shows 3 things:

Not sure if this is what you’re looking for. Trying to answer both of the replies. I hope posting this information isn’t dangerous for me.

Thanks.

[FordGuy61]

Notice the WAN gateway is 192.168.5.1. The TP-Link router picks that up from the ISP device.

Contact your ISP. Their device is functioning as a router, which results in the double-NAT.

Ask them to disable the routing capability and have it function as a modem.

After they make the change you will need to reboot the TP-Link router. It should then display a public IP address as the WAN gateway.

[Angrybob]

@FordGuy61

Ask them to disable the routing capability and have it function as a modem.

When I have them to disable the routing capability and function as a modem, the built-in router will still work as a router, right?

[FordGuy61]

@Angrybob

When I have them to disable the routing capability and function as a modem, the built-in router will still work as a router, right?

The ISP device will function as a modem.

The TP-Link will function as the router (which it is already doing).

Having both devices as routers causes the double-NAT situation.

Changing the ISP device from a router to a modem disables its routing process and eliminates the double NAT situation.

[BigWheel]

Just to be clear here. what is the TP link AXE5400 connected to on it’s physical WAN port?

You said it was not connected to anything else. So I assumed that was the device from ISP or you bought it so you did not have to pay monthly fees for an ISP device.

@Angrybob

and NOTHING ELSE.

[Angrybob]

So the connection comes into the house, and then to the TP link AXE5400. All of our devices then connect to the AXE5400. I’m fairly sure the modem was purchased.

[Angrybob]

I called the IP and they changed their internet to be on bridge mode (as described by the guy on the phone).

Unfortunately, after all the updates, I’m still having trouble with Plex, It behaves just as it had before. The tech sent me, via email, the IP Address, Gateway, Subnet, and DNS.

He told me the router would automatically change and I wouldn’t need to manually add this data once they made changes on their side. I believe changes have been made.

As there is still an issue, let me post the logs again. Remote Access will still change from Green to Red, if you click on other parts of the menu. I’m almost wondering if the change made by the Internet provider wasn’t the initial cause. Unfortunately, I have no idea. Hopefully, a step in the right direction.

Plex Media Server Logs_2025-08-14_10-57-44.zip (4.2 MB)

[BigWheel]

It still shows a WAN ip of 192.168.5.10

Aug 14, 2025 10:53:08.764 [0x16c527000] DEBUG - [Req#d30f] PublicAddressManager: got WAN IP 192.168.5.10 from router

@Angrybob

So the connection comes into the house, and then to the TP link AXE5400

If you plug a computer directly into the wall bypassing the AXE5400 router does it get that same IP for the computer or does it get a real external IP. ( you should be able to see it in the macOS network settings)

[Angrybob]

Hello,

I had to use a different computer, as this iMac doesn’t have an ethernet port. I used a Windows 11 computer.

So I gathered the data with the computer connected to the router, and with it connected directly to the wall.

Through the router, we have

And plugged directly in, bypassing the router, we have this:

Does this info help? Like I said, it’s not my computer I use, but one that’s near the router that is rarely used. The IP addresses do look different, but not by much.

What should I do so that this is always green?

Hopefully, I’m not exposing myself to undue risk posting this info.

Mod Edit: I masked the last two octets of the public IP address. Displaying the private IP address is not a problem. @FordGuy61

[FordGuy61]

@Angrybob

near the router that is rarely used.

What is this “rarely used” router?

The TP-Link router WAN port connects directly to an Ethernet jack on the wall, correct?

What is on the other end of that connection?

Any chance it is the “rarely used” router?

There is still another router somewhere.

Otherwise, the PC would have the 209.147.x.y address when connected to the wall jack.

[BigWheel]

@Angrybob

And plugged directly in, bypassing the router, we have this:

ok so when plugged directly into the wall via the other computer and getting the 192.168.5.11 address mean there is a router on the other side of that wire that is giving giving DHCP with the 192.168.5.x IP pattern

The reason that you see the 209.147.x.x which is a real private IP is that Plex failed with the 192.168.5.10 WAN which is expected so it tried the Ip used when you signed in ( the 209.147.x.x) but that won’t work because you are behind a double NAT. There is some device on the other side of that cable in wall that is giving the 192.168.5.x and you need to figure out what that is.

[Angrybob]

Sorry, I meant the computer near the router is rarely used. Everything plugs into the router.

So it seems there is also something else? I might have to call the IP and ask them if they changed over to bridged mode or not. Otherwise, I’ll have to look and physically follow the wire.

[Angrybob]

I followed the wire into the closet and found that it is connected to a little white box. I’ve never seen it before and don’t know what it is. I’m more unfamiliar with this as this is my parent’s house and I assumed I knew what was attached.

Anyway, this white box has 3 connections. It has one for the power, then, on the top, are two holes for ethernet cables. One hole says POA and the other says LAN. It’s the LAN one that’s connected to the router (the same one I put into the computer that I gathered the data from)

I took the wire from the POA slot and put that into the router but there is no internet at all now. I’m going to put it back and see if there is anything else.

Maybe this sheds some light on it. I hope it does anyway.

I’ll return with further updates.

[FordGuy61]

Thanks for the clarification.

Yes, there is still another device acting as a router somewhere between the TP-Link router and the Internet.

Your ISP should be able to help.

FYI, here is what is happening:

Internet <-----> Unknown Router <----->  TP-Link Router <-----> Plex server, laptops, phones, etc.
 

Unknown router: translates 209.147.x.y to 192.168.5.x addresses. It assigned 192.168.5.10 to the TP-Link router.

TP Link router: translates 192.168.5.10 address to 192.168.0.x addresses. It assigned 192.168.0.80 to your Plex server (displayed in settings → remote access).

The problem is the two translations interfere with port forwarding for remote access.

We need to eliminate one of the translations.

[Angrybob]

After returning the unknown white box to its previous state,

I followed the cable deep into the closet. I thought I knew that room well (as it was my room as a kid 30 years earlier). I found something mounted to the wall. The ethernet cable, from that white box, goes to this wall. Something is mounted on it. From here, the wire (presumably) goes into the wall and wherever this fiber optic network cable would go.

Not sure if you can identify this device by the photo, but is this thing a router?

[FordGuy61]

@Angrybob

but is this thing a router?

It could be. It is the ISP gateway device and could function as a router.

Contact your ISP. Have them confirm their equipment is bridge mode.

Keep them on the line while you check the address using the PC or TPLink router.

If working as desired you will see the 209.147 address and the 192.168.5.x addresses will go away.

[BigWheel]

picture is blurry but going a Google Lens search seems that is a transceiver that converts the optical signal to one that can be used over ethernet.

Fiber XGS-PON CPE - Ubiquiti Store

i’m guessing the white box is the actual modem/router but not sure

Does the white box not have any markings on it for Brand or model number?

If you contact your ISP I would tell them you are trying to port forward in your router but because you are behind theirs you can’t due it causing a double NAT.