Using Orbi RBK12 with bundled modem/router?

[SethOx]

Hi, I’m in the UK and my internet provider is Post Office Broadband. They provided a bundled modem/router, and there doesn’t seem to be any obvious way to put it into bridge mode (I.e. modem only). Looking at their website, it looks like it might not be possible to do this. Is it necessary to put the modem/router into bridge mode to be able to use the RBK12 with the modem/router? If not, how do I set the RBK12 up with the modem/router to make sure it all works? Thanks!

[FURRYe38 · Accepted solution]

No, as the RBR has a firewall running when in router mode so you can use the DMZ for the RBR running in router mode. 

[FURRYe38]

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

Try option #2 first, if that doesn't work, try option#3...

[SethOx]

Hi, thanks a lot for your very helpful reply. I phoned the ISP and they "can't" (i.e. won't) help me put the modem into bridge mode, so I guess that option 1 isn't available to me.

Re option 2, I've logged into the admin page for the modem and I can see how to disable the wifi radios, but I can't see how to "configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the Orbi router gets from the modem".

In the admin page there is a WAN Services section - is this where I can configure the modem in line with option 2? To give more detail, in the clickable WAN services window it says "DMZ disabled" and "DynDNS disabled - 0 Port Forwarding Rules and 0 UPnP Rules". If I click on the window I go through to a more detailed page, that has the following sections: IPv4 Port Forwarding Table, UPnP, DynDNS IPv4 (disabled), and DynDNS IPV6 (disabled). 

Thanks again for your help 

[FURRYe38]

I would look into this feature "DMZ disabled". Find a user manual for yoru model modem online to see if it gives more information or ask you ISP to help out as well. They should be able to help you with this. 

[FURRYe38]

Or lastly try AP mode on the orbi system...

[SethOx]

Thanks for all your help, just one more question - do I need to be more worried about security if I use the DMZ solution?

[FURRYe38 · Accepted solution]

No, as the RBR has a firewall running when in router mode so you can use the DMZ for the RBR running in router mode. 

[SethOx]

Great, thanks!

[FURRYe38]

[SethOx]

Hi, apologies, I thought I had fully understood everything, but hadn't actually done it in practice. Now that I'm doing it, I realise that I don't know how to find the the IP address the Orbi router gets from the modem. How do I do this? (I googled this and the top result provides a default IP address for the Orbi router, but it's the same as the IP address for my existing modem, so I can't use it)

[FURRYe38]

To find the IP address give to the RBR from the modems router, look at the modems connected clients page for this IP address.

You might do a factory reset on the RBR and walk thru the setup wizard. This should change the IP address on the RBR to something else that doesn't conflict with what the modems is using. The RBR should detect this and change to maybe a 10.0.0.1 address schema...

[SethOx]

Thanks a lot, that worked and it’s all working!

[FURRYe38]

Awesome. Good to hear. Enjoy now.