Visitor

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3 Messages

Wednesday, March 18th, 2026 10:31 PM

Closed

Bridge Mode Issue – Router Not Receiving IP from Modem (Motorola MG7700 + TP-Link Deco)

Hi, I’m trying to reconfigure my home network and could use some assistance.

I have a Motorola MG7700 cable modem/router (software version 7700-5.7.1.21) and I am attempting to place it into bridge mode so I can use a **TP-Link Deco XE75 Pro mesh system as my primary router and Wi-Fi network.

Here’s what I’ve done so far:

  • Reset the MG7700 to factory defaults

  • Verified that it receives a valid public IPv4 address when operating in normal (router) mode

  • Set up the Deco system successfully in router mode (double NAT), where it receives a private IP (192.168.x.x) and internet works

  • Enabled MAC address cloning on the Deco (using the client MAC)

  • Enabled “Primary Network Bridged” on the MG7700

  • Performed multiple full power cycles (modem first, then router)

However, once the MG7700 is placed into bridge mode:

  • The modem no longer shows a valid IPv4 address (---.---.---.---)

  • The Deco does not receive a public IP (WAN IP remains blank or 0.0.0.0)

  • The Deco indicates no internet connection (red status light)

  • Wi-Fi clients connect but report no internet access

It appears that the Deco is not being assigned an IP address from the ISP when the modem is in bridge mode.

Could you please advise:

  • Whether there are any provisioning or MAC address binding issues on your end

  • Whether the modem needs to be reprovisioned after switching to bridge mode

  • Whether you recommend releasing/renewing the DHCP lease or clearing any cached MAC addresses

  • If there are any compatibility issues with the MG7700 in bridge mode on my service

I’d appreciate any guidance on how to ensure the Deco router can properly obtain a public IP address through the modem in bridge mode.

Thank you for your help.

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Accepted Solution

Visitor

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3 Messages

5 hours ago

I ended up resolving this by replacing my modem with a Motorola MB8611 (a standalone DOCSIS 3.1 modem with no built-in router). After that, I simply went through the standard Comcast Xfinity activation process, and everything worked as expected.

With the new modem, there was no need to use bridge mode, and my router was able to obtain a public IP address immediately.

Official Employee

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1.4K Messages

3 days ago

@user_1uxtc5 Thanks for adding a post to the community. Is the MG7700 a customer owned modem? 

Visitor

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3 Messages

7 hours ago

This issue has been solved. Thanks!

Official Employee

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996 Messages

Hello @user_1uxtc5, Thank you so much for the update. You're very welcome! I'm glad to hear your concern has been addressed and everything is resolved. We truly appreciate you taking the time to let us know, and wishing you a wonderful week ahead!

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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Expert

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116.8K Messages

@user_1uxtc5​ 

Would you please share with the community what the solution for this issue was so that all readers here may benefit from it ? Thank you.

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? Please mark an Accepted Answer!tick

Expert

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116.8K Messages

4 hours ago

Thank you for returning here with that info ! Now closing your solved topic.

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