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user_f9ciha
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Tuesday, August 5th, 2025

New xb8-t: LAN ports disabled in bridge mode?

Hey there - have a brand new xb8-t and am attempting to use an Asus BT10 mesh router. 

When I place the xb8-t in bridge mode, no LAN ports provide internet. I have confirmed with via the router connection and also by connecting a PC to the modem directly via Ethernet.  If I understand correctly one port should remain active in bridge mode.  Have performed a full factory reset of both the modem and router twice. Firmware it up-to-date. Current setup: I've just disabled all wi-fi radios on the xb8-t.

When the vb8-t is not in bridge mode, all ports provide internet and the ASUS is OK - though I do encounter occasional DHCP errors. 

Any ideas?

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16 days ago

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EG

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114K Messages

3 months ago

Are you power cycling / rebooting the XB8 after you put it into bridge mode ? And before you connect the computer to it ?

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user_f9ciha

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Ooh, thanks, I feel like I power cycled but probably not with everything unplugged. Replying below....

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2 months ago

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XfinityDemitrius

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I appreciate the detailed response @user_f9ciha. I would first perform with a computer hardwired to the modem to verify that the Internet and network is function. If the computer is able to connect, then we know the XB8 is working correctly. I would check the network in the following order:

Test with Computer
1) Unplug everything from the XB8-T and enable bridge mode. 
2) Power down/unplug both the XB8 and Computer, while connected with an Ethernet cable.
3) Power up the XB8, wait for white LED. 
4) Power up Computer and open browser.
5) Test Internet connection. 
6) If able, see if the computer is getting a valid IP address using the command prompt. 

If the Internet is accessible and works, you would want to perform the same steps, but with the ASUS router. 

Test with Router
1) Unplug everything from the XB8-T and enable bridge mode. 
2) Power down/unplug both the XB8 and Router, while connected with an Ethernet cable.
3) Power up the XB8, wait for white LED. 
4) Power up router and wait for full boot.
5) Connect computer to router.
6) Test Internet connection. 

Please give this a try and let us know if you run into any issues or if these steps successfully work. Hope to hear from you soon. 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
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2 months ago

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user_f9ciha

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Thanks - unfortunately none of this was successful. I did all of these steps - got the same failures. Repeated them with a second mesh router (the old one) - same failures. Computer connects fine via cable after every power cycle. Routers never do. 

If I deactivate bridge mode, both mesh systems connect fine. Something is happening in bridge mode that is preventing my routers from connecting and we now know through your tests and confirmation via Ethernet connected PC that it's not the port.  

To be SUPER SAFE I wanted to rule out the Asus router as the problem so I reactivated my old Arris Surfboard modem - the Asus router connected successfully, instantly. 

The problem lies with the xb8-t, and it's not the port. Any ideas?

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2 months ago

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XfinityChristy

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user_f9ciha Thank you for performing these additional tests. Since you have ruled out the port and your equipment, the next step is to further investigate the gateways configuration and functionality. To get started, please send our team a Direct Message with your full name, the name listed on the account (if different), and the service address associated with your account. 

 

To send a "Direct Message":

Click "Sign In" if necessary

Click the "Direct Messaging" icon at the top of the page (it looks like a text bubble)

Click the "New message" (pencil and paper) icon

Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list that appears. The "Xfinity Support" graphic replaces the "To:" line

Type your message in the text area near the bottom of the window

Press Enter to send it

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

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2 months ago

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XfinityDemitrius

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2 months ago

Hey @user_f9ciha. Thank you for visiting our official Xfinity Forums Community support page. When in 'Bridge Mode', one Ethernet port should be active. After enabling bridge mode, have you attempted to power cycle both the modem and router to get a proper network handshake between devices and see if it gets a valid IP?

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user_f9ciha

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2 months ago

Thanks both for replying!

I really do feel like I power cycled the modem after popping it into bridge one in at least one of my attempts. Perhaps not! To be clear, you are recommending these steps in this order?

1) Unplug everything from the XB8-T and enable bridge mode. Wait for white light. 

2) Power cycle XB8-T. Wait for white light. 

3) Power down ASUS BT10.

4) Plug ASUS BT10 into one of the XB8-T's ports (any port will work, including the 2.5?)

5) Power up ASUS and wait for handshake?

Is that correct?  How can I confirm that the ASUS got a proper IP?

Thanks for the help so far!

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EG

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114K Messages

2 months ago

Yup.

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user_f9ciha

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OK, will give it a shot - thanks again!

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2 months ago

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u84six

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2 months ago

I'm not sure why your ports are unavailable in bridged mode. I have an XB8 and after putting it in bridged mode, all 4 ports are working. Maybe the ports are working but your pc is unable to connect? Try flushing DNS by issuing the command: ipconfig /flushdns

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user_80l7bv

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16 days ago

Same exact issue as original poster. I can get the XB8-t to connect to my mesh system in bridge mode only if I enable the following option on my gateway:

Hardware->LAN->LAN Ethernet Port 2 option: "ANote: Associating Ethernet Port 2 to XFINITY HOME network will remove the port from your home network"

It works, but only at 1000Mbps. It will not work with the 2500Mbps port. (port 4). My service level is more than 1000Mbps.


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