CAX80 Modem Mode issue - IPs from different areas

[ViperXII]

I’m having a real weird problem I’m hoping someone can help with.

I recently purchased a new, more powerful router that I needed for a larger home. As such, I decided to use my CAX80 in Modem mode (router off) so I didn’t need to buy a new modem. However, in Modem mode the connection is making my computer (and related services like the Speedtest app) think it’s in different cities due to the IPs that the CAX80 is pulling in this mode from Xfinity. I live in Seattle, but my computer will think it’s in Chicago, Sunnyvale CA, etc.

Here’s another weird symptom - when the CAX80 is back in Router mode, the problem goes away and the location is fixed.

To note: I’ve performed tests with the CAX80 in modem mode direct connected to my computer, in modem mode connected through my router, and in router mode as well. I’m in IT so I’ve troubleshot the crap out of this thing every way I can think of. I believe I’ve isolated the symptom solidly to the CAX80 when the router functionality is off.

Hope someone can help!

[plemans]

2 things. 

1. The isp actually assigns the ip address. Not sure why it'd change in modem only mode but its not something the user controls but the isp. 

2. why not leave the CAX in router mode? Then have the other system in access point mode. Just make sure they're using different ssids and are on different wireless channels to prevent interference. You can put the devices close to the CAX on it to take some load of the other system you're using. The CAX is quite capable and is being very underused in modem only mode. 

[ViperXII]

Thanks for the reply! 

So, interestingly... the issue ended up being both the new router and the CAX80 in Modem mode. Bad luck for me I suppose.

I swapped the CAX80 for an Arris S33 and the location issue vanished when connecting directly to the modem. I also exchanged the other router (after extensive testing with the new modem), and that fixed the issue as well. I'm thinking there was some sort of hidden firmware issue out of the box that caused the device to think it was in another state. Very weird. 

Regarding why I don't just keep the CAX80 as a router, 2 things:

1. I want a mesh system that's a bit friendlier for others in my household to use than setting up an AP with a separate network.

2. The CAX80 5GHz network photo and video upload issue is a dealbreaker for me and Netgear seems like they aren't prioritizing fixing the problem. Leaves me to look at other options since I shouldn't have a handcuffed 5GHz network.