Orbi RBK752 No Internet Connection

[duffymo]

Xfinity is my ISP.  The cable modem connecting to the internet is locating in a room above my garage, connecting to my desktop.  I extend wi-fi through the downstairs portion of my house using three of their wi-fi extension pods.  

I purchased an Orbi RBK752 in hopes of improving my wi-fi access.

i logged into my Xfinity modem as admin, enabled bridge mode, and restarted the modem.

I powered up both the Orbi router and satellite, connecting the cable modem to the router using Ethernet port #4.  I set up the Orbi network using the iPhone app.  It said it had no problem getating an Internet connection.  I completed the setup and came downstairs to check the satellite.  It showed a blue light, which means the connection was strong.  

I got on my laptop and saw the Orbi network as a choice for wireless connection.  I chose the Orbi network and entered the password.  My phone told me that it could see both my iPhone and my Ubuntu laptop connected to the Orbi wi-fi network.  It looked like I'd done everything correctly.

I was disappointed when my laptop could not access any web pages.  No hosts could be resolved; no DNS server was visibile.  It was as if there was no connection to the Internet, in spite of the feedback on my phone.

I had to disconnect and turn off the Orbi router and satellite and restore the Xfinity extenders to restore Internet access.  

What did I miss?  Why couldn't my laptop find a DNS server when the network said an Internet connection was available?

[FURRYe38]

Please post about this over in the Orbi AX forum:

https://community.netgear.com/t5/Orbi-AX/bd-p/en-home-orbi-ax

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?

Power OFF the ISP Modem and RBR for 1 minute. Then back ON with the modem first, then the RBR. Be sure to use port #1 on the modem for the RBR ethernet cable. 

[duffymo]

How to move a question?  Copy, paste, and create a new question?  Or is there a better way.

Already did all that.  No joy.

[duffymo]

Xfinity voice and data modem:

CISCO DPC3941TSerial #: 48F7C0D3CE0D

Firmware is up to date.

[FURRYe38]

Your ISP modem already has a router built in. This would be a double NAT (two router) condition which isn't recommended. https://kb.netgear.com/30186/What-is-Double-NAT
https://kb.netgear.com/30187/How-to-fix-issues-with-Double-NAT
Couple of options,
1. Configure the modem for transparent bridge or modem only mode. Then use the Orbi router in router mode. You'll need to contact the ISP for help and information in regards to the modem being bridged correctly.
2. If you can't bridge the modem, disable ALL wifi radios on the modem, configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the Orbi router gets from the modem. Then you can use the Orbi router in Router mode.
3. Or disable all wifi radios on the modem and connect the Orbi router to the modem, configure AP mode on the Orbi router. https://kb.netgear.com/31218/How-do-I-configure-my-Orbi-router-to-act-as-an-access-point and https://www.youtube.com/watch?v=H7LOcJ8GdDo&app=desktop
https://kb.netgear.com/26765/Disabled-Features-on-the-Router-when-set-to-AP-Mode

Try option 3 first to see if this works. 

Be sure your using a good quality LAN cable between the modem and Orbi router. CAT 6 is recommended. 

Be sure you use LAN#1 port on the back of the modem...