XR500 Wifi No Internet

[Jl92]

5268 AT&T modem is setup in DMSPlus mode to allow all traffic to XR500. It was working fine for 2 months. Now, I cannot access internet whether hard wired or over wifi. All devices see the wifi and can connect. From PC, i can ping web sites. Router has IP address from ISP. Rebooting and factory resets sometimes give brief periods of internet access from 10 seconds to an hour. If I connect direct from the 5268 modem to the PC (leaving XR500 out) I can connect to internet. I do not have Content filtering or Traffic Monitoring on. I swapped out ethernet cables and tried different ports. I checked for and have the latest firmware on the router. No settings were changed by me from the period it was working to when it was no longer working. However, now I have the latest firmware. No devices can access internet. ISP (AT&T) says it’s not their equipment.

[Jl92 · Accepted solution]

I got the Double NAT issue a couple more times. On the Modem’s firewall rather than DMZ, i changed the firewall to allow xbox one game traffic specifically to pass through. It looks like this fixed it without blocking all internet access as DMZ mode had done.

Thanks by the way for all your help.

[FURRYe38]

Using v56 FW:

https://community.netgear.com/t5/Nighthawk-Pro-Gaming-Routers/New-XR450-XR500-v2-3-2-56-Firmware-Upd...

Has the wifi radios on the ISP modem been fully turned OFF? 

How close is the XR router from the ISP modem? 3 feet is recommended to start. 

[Jl92]

Yes ISP radios are off. Router and modem are about 18 inches from each other and always have been. PC cannot reach internet via LAN. Though from cmd line, I can ping websites. In case it matters, on the reply from ping, the first packet is always lost. It says General failure. Then I get three replies. ISP had me run tracert from cmd line and according to them it was normal. If i use the AT&T modem w/o the XR500, I can connect normally to Internet via LAN. If i turn the ISP radios on, I can also connect to internet through those (with XR500 off).

[Jl92]

the updated firmware came out on 8/16? I did have auto update on. I first had loss of internet on 8/15 but reboot fixed it. Since 8/16 no internet access using the XR500. I suppose it could be coincidence but isnt that a red flag? Can I roll back the firmware? How would I do that?

[FURRYe38]

Try this, disable the DMZ on the ISP modem and configure the XR500 for AP mode. See if the problem continues with this mode. 

Has a factory reset been performed since applying v56? 

Instead of using the auto updater on the router, try manually downloading the v56 FW file and apply it with IE11 or FF or Opera. After it's re-loaded again, do one factory reset and setup from scratch. Configure router mode. To see if the ISP or DMZ could be an issue, I would first not use DMZ on the modem, just run the XR with the modem in router mode. See if the problem still appears or not. If not, try enabling DMZ on the ISP modem for the XR router and test again. See if the problem still appears. 

You can downgrade FW as well. Lets try the above first.

[Jl92]

Also, after factory reset, XR500 says internet detected but then on next step of setup, the speedtest fails to detect speed. Next steps appear normal including properly checking for firmware updates. It shows i have the current v56.

[FURRYe38]

Ok, sounds like there maybe a problem between the XR and ISP modem. 

Try the suggestions I just made...

[Jl92]

Disabling DMZ mode fixed it with XR500 in Router mode. I'm not a technical person, but if you can, could you explain what this did? It seems like the last thing that would fix the issue, and previously, it wouldn't work UNLESS it was in DMZ mode.

I did see a Double NAT on the XBOX One, but after a retest it showed Open.

[FURRYe38]

Sounds like the DMZ feature on the ISP modem isn't working as expect. 

IF you have OPEN nat now, I would leave the system alone. 

[Jl92 · Accepted solution]

I got the Double NAT issue a couple more times. On the Modem’s firewall rather than DMZ, i changed the firewall to allow xbox one game traffic specifically to pass through. It looks like this fixed it without blocking all internet access as DMZ mode had done.

Thanks by the way for all your help.

[FURRYe38]

Good to hear. Thanks for letting u know. 

Please post the firewall configurations here if you don't mind so other will know. 

Please mark your thread and solved too. 

Enjoy.