Visitor

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2 Messages

08/25/2026 12:43 AM

Repeated intermittent DOCSIS outages – LAN stays online while Internet drops

I’m having repeated intermittent Internet outages on an XB7 (CGM4331COM). Wi-Fi/LAN stays working and 10.0.0.1 remains reachable, but Internet connectivity drops and the gateway sometimes turns red. During the latest outage, 10.0.0.1 responded to ping while 1.1.1.1 did not.

On Aug. 22 I captured another outage while it was occurring: downstream remained locked at ~40 dB SNR, but upstream showed Not Locked, Modem Status was Disconnected, and WAN connectivity was lost. The connection later recovered. Similar drops have happened repeatedly since then.

Please check the CMTS/modem history, upstream ranging/T3-T4 events, return-path noise or signal issues, and determine whether this is a line/plant issue or a failing XB7. I need root-cause troubleshooting rather than another gateway restart.

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Visitor

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2 Messages

30 days ago

I'm having the same issue in Westminster MD, high packet loss, disconnect, reconnect. Each event lasts 30-90 seconds. Support assistant just keeps telling me nothing is wrong reboot again. That's not the answer. Need some real troubleshooting. 

Official Employee

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2.5K Messages

@user_y6v6fk are you seeing your modem turn off or reset? Or do you see packet loss pinging specific websites only? 

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Visitor

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2 Messages

@XfinityJosephA​ No power issues modem, gateway, etc are on ups. Its hard to catch the connecton lights since the modem is not in a visible location unless I'm in the utility room. The gateway looses upstream connection randomly thorughout the day. 30-90 second disconnects. I've run all the normal troublehsooting steps, changed the jumper between modem and gateway just to be sure. I remvoed the lightening arrestor and checked it with my VNA (I'm an engineer & have test equipment) no problems, left it out for 24 hours no change. My nextdoor neighbor is having the same issue and the times line up so I suspect a failing line amp somewhere nearby. 

I'd just like to get a technician out at this point. every time I try it ends in frustration trying to get the assistant to not try to do the same troubleshooting its just done. Every time I try to call I give up on hold. Maybe I missed something or the modem (only 6 mo old) is bad but I doubt it since it passes all tests and its debug logs just show signal loss. 

Gold Problem Solver

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27.7K Messages

30 days ago

... repeated intermittent Internet ... XB7 ... 10.0.0.1 responded to ping while 1.1.1.1 did not ...

10.0.0.1 is the local private IP address of the XB7 itself and should always respond to ping when the device is powered up. 1.1.1.1 however is an IP that requires access to the public Internet. Network connection problems that affect both Ethernet and Wifi connections to the Internet are often due to poor coax connections or damaged coax cable, usually in or near your home. Running the coax through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power. 

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you can't find the problem or you'd rather have Comcast take care of it and an employee does not respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

Visitor

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2 Messages

@BruceW

Thanks. I’ve already completed the basic troubleshooting and captured the failure while it was happening: LAN/10.0.0.1 remained reachable while Internet was down, and on one outage the XB7 showed upstream Not Locked and Modem Status Disconnected. The Xfinity Assistant now only offers a charged “Professional Installation.”

Could an Official Xfinity Employee please review this as a recurring existing-service outage and help me arrange the appropriate repair/trouble call?

Official Employee

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434 Messages

@user_10jjay30 Thank you for the detailed information and for capturing the modem status during the service interruption. We appreciate the detailed troubleshooting you have done and will be glad to take a deeper look. Please send us a direct chat message with your full name and complete service address to “Xfinity Support”
Here are the detailed steps to direct message us:
Click "Sign In" if necessary
Click the "Direct Message” icon.
Click the "Start new conversation" (pencil and paper) icon.
In the "To:" line, type "Xfinity Support."
As you type, a drop-down list will appear. Select "Xfinity Support" from that list
An "Xfinity Support" graphic will replace 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 as Best Answer.tick
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