RBR850 Can't get internet from Xfinity xFi Gateway

[popechild2]

Hi, I've spent about 9 hours on this today, so really hoping someone here has some ideas to break the logjam!

I've got an RBR850 and 5 RBS850's. FW 7.2.6.31. I've been using them for a few years pretty successfully. About a month ago Xfinity convinced me to replace my Netgear CM1100 modem with their xFi Gateway. My system has been less stable since, so I called Xfinity today and asked if I could use my old modem again without losing my existing package. They escalated me to a tech supervisor who tried a few things to get their system to accept the old modem on the xFi package but couldn't get it to work, so they said I'd need to go back to the xFi modem. 

That's when the real problems started. Ever since they did whatever they did, I've been unable to get my RBR850 to get an internet signal from the xFi. Again, this has been working fine aside from some performance hiccups for about 6 weeks until today. I spent a few hours on the phone with Xfinity tech support and eventually went to the Xfinity store and they swapped out the modem, but it still won't connect. 

1) I can use the xFi modem in WiFi mode fine. 

2) I can put the xFi modem in bridge mode and connect my laptop directly to ethernet port 1 and access the internet that way fine.

3) If I connect a spare Netgear Nighthawk AX5 router to the modem while the modem is on and in bridge mode, it will at first not see the internet signal from the modem. But if I leave it connected and restart the modem, the Nightkawk will get the internet signal after the modem restarts and works fine.

4) But no matter what I try, I cannot get the RBR850 to see internet. And what's even weirder, if I try to restart the xFi Gateway while it's connected to the RBR850, the xFi won't even lock onto a signal itself. Rather than go through the bootup flashing sequences and land on solid white, it goes to blinking white and never stops. If I disconnect and reboot, the modem locks on solid white and gets a signal again. Then I can connect the RBR850 and the light stays solid white, but it doesn't actually get internet, and if I leave it connected and reboot the modem again, the modem just blinks the white light and never connects.

A few more details that may be helpful:

- At this point I've disconnected all the satellites and have (twice) factory reset the RBR850 by holding a pin in the reset button for 30 seconds or so. 

- When the factory reset has happened, if I let the modem boot up disconnected so it gets the solid white light, or if I connect it to the Nighthawk and confirm the internet is working on it, then switch the cable to the RBR850, I get an error message when trying to do a fresh setup of the Orbi through the wizard that says "No Ethernet Cable is plugged into the Router Internet Port". That made me wonder if the port had gone bad, which would be a heck of a coincidence since it's been fine until the moment I tried to switch modems today, but the next point makes me think the port is fine.

- If I skip the wizard and try to set it up manually, when I go to the "Connected Devices" screen in the RBR850's admin, I occasionally see a device with the MAC number of the xFi modem. It comes and goes, but it definitely show up at least most of the time. And this may not mean anything but it seems odd to me: when the xFi modem shows up in the Connected Devices list, it has an ip address in the assigned range from the RBR850, as if the RBR850 thinks it should be assigning an IP to the modem rather than receiving internet from the modem. And yes, the modem is definitely plugged into the Internet port on the RBR850 and not into one of the four LAN ports. 

Any ideas or suggestions? I'm completely at a loss at this point. I've got a service appointment with Xfinity setup for Monday but I'm sure they'll just tell me it's the Orbi's fault since it works fine on its own and even in bridge mode with the Nighthawk. Maybe it's just a really unfortunately coincidence and the RBR850 broke somehow at the exact time I was trying to reactive my old modem? 

Hoping someone has an idea. Happy to try just about anything at this point!

[CrimpOn]

This started when you wanted to upgrade the Xfinity service to a higher speed and Xfinity claimed that the Netgear CM1100 was not compatible with the higher package, correct?

This web site appears to state that the CM1100 DOCSIS3.1 modem is both compatible and certified with Xfinity.

https://kb.netgear.com/000063930/Which-ISPs-are-compatible-with-my-NETGEAR-cable-modem-or-cable-mode... 

Did Xfinity change your service from cable to fiber?

[popechild2]

Did not change to fiber, we're still on cable. And our service didn't change when the issue started. Our service changed about 6 weeks ago and we've been using the new modem mostly fine for that 6 weeks. The problem started when I asked them to switch me back to the CM1100 because the xFi has been more inconsistent, mostly with speed fluctuations. Because they had switched me to a new xFi complete plan, at first they stated I couldn't use the CM1100 anymore without losing the free unlimited internet that's part of the xFi plan. Then they tried to reactivate my CM1100 anyway for me, couldn't get it to work without changing the plan, so abandoned that effort and told me I just needed to keep using the xFi or else lose the unlimited internet. 

That's when the issue started.

[CrimpOn]

(sorry to display even more ignorance about Xfinity.......)

Is the "free unlimited" plan a critical part of the decision?  (Does Charter/Xfiinity have an account information site that shows how much data has been used in recent months?  Are you perilously close to breaching some limit?)

[popechild2]

This increasingly appears to be a problem with the RBR850. 

1. I moved the ethernet to the multi-gig port 4 on the modem. No change. Works fine in bridge mode with the Nighthawk. The Orbi RBR850 does not see an internet connection.

2. Not sure if this is related to moving to port 4, but the thing I was seeing before where the xFi modem couldn't lock onto a signal and keep a solid white light when re-started while connected to the RBR850 is no longer happening and the modem can happily reboot and keep a solid white light. But the RBR850 still doesn't see an internet connection. Have rebooted the RBR850 also.

3. I'd assume the internet ethernet port on the RBR850 has gone bad, except when the modem is connected to it, the modem shows up in the Connected Devices list.

@CrimpOn, I am aware the CM1100 cannot support Xfinity's max speed. But it can support 1Gbps, which is fine with us. We have the 1200 Gbps plan with Xfinity and don't mind if we're only getting 1Gbps if the connection is more stable. But we do go over Xfinity's data cap, so at this point it would cost us $30/mo more to go back to the CM1100 and pay for the unlimited internet.

[popechild2]

So this seems weird to me. Looking at the RBR850 admin page, can someone help me decipher this?

ModestMBA is the laptop I'm using. The other device (C4:50:9C:42:A6:B6) is my modem. Is it normal that the router would be assigning an IP address (192.168.1.3) to the modem? That isn't what I would expect and seems to be indicating that it doesn't realize the modem is a modem or something?

Then in the image below, there's no activity showing but there IS activity showing on LAN1. The only ethernet cable connected to the router is on the yellow LAN port (visually double-checked). Wouldn't I expect to see activity showing here on the WAN port and not on the LAN1? Taken together with the IP address thing above, it almost seems like the RBR850 thinks the modem is actually connected to LAN1 instead of WAN, and therefore doesn't know it's a modem and is instead trying to assign an IP to it like a regular connected device. But I'm not sure if that's just me not understanding how this typically works?

[popechild2]

One more data point. If I keep watching the connected devices page, occasionally a third item pops up. This shows up as a wired device, but the only wired device is the modem. It appears to have an external IP address, like I would expect the modem to have. But the MAC address is not the MAC address listed on the modem. When I goggle it, it brings up another manufacturer that appears to make chips that are sometimes present in modems. 

[CrimpOn]

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@popechild2 wrote:

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This would seem to indicate that the Orbi router is not connected to the xFi box at all. (WAN port status is blank.)

[popechild2]

Yes, that's what's strange to me. Because the xFi is definitely connected to the Orbi and it's definitely connected on the yellow Wifi WAN port. And the Connected Devices list shows the MAC address of the modem, so it's "seeing" the modem somehow, which again is connected to the yellow WAN port.  

Also, nothing is connected to the LAN1 port, but there's activity showing there. 

[CrimpOn]

I am sometimes too fixated on terminology.  In this discussion, the term modem can refer to

• The Netgear CM1100 modem, or it can refer to
• The xFi box? (which specific xFi is this?)

At no time are both the CM1100 and the xFi operating at the same time?

[popechild2]

After from the brief period of time that the Xfinity agent was trying to help me swap back to the CM1100, which is when all this trouble started, I have been exclusively using the xFi XB8 Gateway. That's the modem I'm having all the trouble with.

[CrimpOn]

Thanks for being patient.  Is there a specific reason to put the XB8 into Bridge Mode?

[popechild2]

I'm using the RBR850 as my router along with 4 satellites to ensure full coverage in our house. In order to use the RBR850 as the router, the xFi needs to be in bridge mode. The XB8 can't cover the full house.

I've used the RBR850 and satellites for quite awhile now. And for the last 6 weeks have used it with the XB8 in bridge mode. So something has obviously changed which is preventing it from working now. Since the XB8 still works in bridge mode with the Netgear Nighthawk, it would seem to indicate the problem is with the RBR850.

[CrimpOn]

I ask because having a customer router connected to an ISP router is quite common.  I believe that thousands of customers open the box containing their new WiFi system (Asus, Amazon eero, Google Mesh, Linksys, TP-Link, Netgear, etc.), plug the cable into their ISP router and start using it.  Many of them do not even change the default WiFi credentials.

This creates what is called a "Double NAT" condition which interferes with specific internet usage.  Certain internet gaming, internet file sharing, and accessing home devices from the internet can be quite complicated with a Double NAT. (not impossible, but more technical to set up).  If "it works great" with the XB8 in the default mode and does not interfere with something you seriously need to do, then that might be the solution.

On a lark, I deliberately set up a "Triple NAT": Orbi router -> connected to Linksys router -> connected to Orbi router. All of them in router mode.  With a computer connected to that final router, I could stream video, browse the web, do email, etc. just fine.  Setting up internet file sharing was a chore - but possible.

No one seeks out a Double NAT on purpose.

A random comment on the nighthawk experience mentioned in message 1, when disconnecting the primary device from a modem (including CM1100 and XB8) and replacing it with another device, it is almost always necessary to restart the modem.  It has already learned the MAC address of whatever it has been connected to and will need to start over to learn the MAC address of the new device.

[popechild2]

Couple of updates. 

1) I tried taking the XB8 back out of bridge mode and the Nighthawk did indeed still work fine, but the Orbi still did not passthrough any internet.

2) I picked up a new RBR850 from the store to try to confirm for sure whether it's purely the Orbi's fault. This one connected right up (with the XB8 back in bridge mode) just fine. Works great. 

Of course I'd rather not have to buy a brand new router if there's a way to get my current one to work. It clearly is having some sort of issue. Maybe it's a bad WAN port after all. Just super weird that the Connected Devices list shows the XB8 when it's connected, so it's obviously "seeing" something on that port. But not apparently working beyond that.

I'm going to reach out to Netgear support tomorrow and see if there's anything else they can think of to do, or if this is just a bricked router at this point.

If the WAN port on the router doesn't work right but it otherwise seems to function fine, is there anything else at all it's useful for? Is it possible to put the satellite firmware on the router and just use it as a satellite? Or is the entire box junk if the WAN port goes bad?

[CrimpOn]

• I am not aware of any explanation of a method for converting an AX series Orbi router into a satellite. (A method was published years ago for converting the original RBR50 into an RBS50 satellite.)
• It might be worth doing one more Factory Reset on the old Orbi router.  Connect a computer directly to the old router and then connect the old router to the current system to see if the WAN port recognizes the connection.  After a Factory Reset, that old router should come up in a "please configure me" mode.  It prompts users to use the Orbi 'app' for configuration, and I scroll down to the prompt which says, "I do not have a cell phone" so that I can use the computer that is connected to it. (What business is it of Netgear's whether I have a cell phone or not????)

[popechild2]

All satellites are disconnected from power and ethernet.

I’ll update if there’s any further guidance after talking to support.

[RedsonRising]

Any updates yet?

[popechild2]

Support wasn't any help, but I eventually bought a used RBR850 since I couldn't figure out anything else to try and the new (used) one connected right away. So clearly some sort of hardware problem, though what exactly it was I couldn't say. The ports showed activity, the wifi worked, it just somehow either wouldn't receive or pass through the internet signal from the modem. And it was out of warranty, so nothing I could really do but buy a replacement.

[FURRYe38]

Has anyone tried a stand along modem? XF supports BYOM so would be an alternative and something to try. ISP Gateways can be problematic with external WiFi router systems. I now that others have used NG CM series modems with this ISP and they work well. 

@donawalt 

@plemans 

[donawalt]

It sounds like replacing the RBR850 fixed the problem. I assume you are not in warranty period to get it replaced, but you bought another 850 anyway.

FWIW I have a NG CM3000 @FURRYe38 and it works great, but the XB8 (bridge mode) -> 850 seems necessary to avoid being charged for going over the data cap (this doesn't exist in the northeast, but does everywhere else in the country with Comcast).

So it sounds like problem solved now with new 850? Or are there other outstanding issues still?

[popechild2]

No other outstanding issues. Just very odd that everything was working completely fine until exactly the moment I tried to switch modems, then suddenly the 850 can't get internet from the modem it was previously working fine with, but a replacement 850 works fine. 

Who knows. One of those things I just don't have additional time or energy or enough knowledge to continue looking into.

[FURRYe38]

What is the brand and model# of the new modem?

Did you power OFF both modem and RBR for 30 seconds, then back ON with the modem first, then 30 seconds later, power ON the RBR? 

[popechild2]

It's the XB8 from Xfinity. Tried as many combinations of restarting, factory resetting, etc as you can imagine over dozens of attempts. Lots of info in the thread above about it all.

[FURRYe38]

Ok, thought you might have got a non ISP modem. Ok. 

Something you might check into. Seems like these ISP modems are causing problems.