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New Xfinity CGM4140COM setup with Nighthawk R7900P issues

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Regular Visitor

New Xfinity CGM4140COM setup with Nighthawk R7900P issues

Just upgraded to the new Technicolor CGM4140COM WiFi enabled box.  The range of the wireless does not connect to my devices in my backyard like my Netgear Nighthawk R7900P did with my previous modem that did not have wireless.  

When I setup the Xfinity modem to bridge mode, the IP address is in the 73.x.x.x range and the MAC address is different than what is on the bottom of the box.

When I disable bridge mode, the IP range is 10.x.x.x and the MAC address is the same as tthe one on the bottom of the box. 

The problem I'm having is determining which mode to use with my Netgear so I can use the wirelss on that device to meet my coverage in the backyard.

I'm usting Port 1 on the Xfinity modem to the internet port on my Netgear and also using the Xfinity supplied RJ45 cable.

When I go into the Netgear setup, and look at the internet settings, there is no IP address that shows up so it appears no DHCP on the Xfinity in either bridge or non-bridged mode.

If I connect the cable to my Macbook Pro, I can see the IP address and I've entered that manually into the internet settings on my Netgear but the internet light is still red on the Netgear.

I've tried disabling Wi-Fi on the Xfinity box and connecting to my Netgear and stil the same issue. 

 

Any ideas on how I'm supposed to setup the internet settings on my Netgear?  Do I use a static IP address, subnet and gateway or DHCP?  Do I need a username and password?  I'm to the point where I'm going to take this back and buy a supported cable modem with no wireless capabilities. 

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Expert

Re: New Xfinity CGM4140COM setup with Nighthawk R7900P issues

Right. No point in using it in bridge mode with your own router that is performing better anyway. Get a plain vanilla cable modem and save the rental fee. It will pay for itself in fairly short order !



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Regular Visitor

Re: New Xfinity CGM4140COM setup with Nighthawk R7900P issues

Thanks EG!  Do I have to use the devices listed here https://www.xfinity.com/support/devices/#auth or will any basic cable modem work?

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Expert

Re: New Xfinity CGM4140COM setup with Nighthawk R7900P issues

Yes, you do.



I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!