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Lost ability to change WAN IP address by changing MAC address. Can only get internet with a specific MAC address.
For almost 30 years I've been able to do this with comcast/xfinity internet service. I have an Arris SB6183 modem and a Netgear WNR2000v2 router (neither are comcast supplied).
Two weeks ago I changed the MAC address in my router to get a new IP like I had been doing for 30 years. When the Modem and router restarted, I had no internet at all.
I could get to my router config at 192.168.1.1, but I could not get to the cable modem status page on 192.168.100.1. I changed it back to the previous MAC and had internet again with the same previous WAN IP address. I could also get to the modem status page.
Next I removed the router from the equation. I connected my first computer, that has the MAC address that works, directly to the cable modem via ethernet cable. Cycled modem power and It worked fine.
Next I connected my second computer with a different MAC via ethernet cable directly to the modem. Cycled modem power and had no internet at all. Again I also could not get the the modem status page on 192.168.100.1. All lights on the modem appear as connected.
After I put the working MAC back in and got online, I logged into xfinity and went though troubleshooting although there was no option for this situation. I choose the no internet option and it did a check of signals and modem and reported everything was normal and working.
I also tried powering down my modem and left it off overnight for 10 hours. It still had the same WAN IP when I powered it up again.
Like I said, this all just started 2 weeks ago.
EG
Expert
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120K Messages
2 days ago
Have you ever tried hard resetting the 6183 to factory defaults by pressing and holding in the recessed reset button on the rear for 25-30 seconds ? This can sometimes clear up some weird behavior issues.
BTW, that modem is no longer supported by them. The MAC address caching circuitry may be malfunctioning. It may be time to retire that dinosaur. That router is a bit long in the tooth as well.
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XfinityCliff
Official Employee
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512 Messages
3 hours ago
Thanks @user_3zero824wzz for sharing the detailed troubleshooting you've already completed here on our Xfinity Community forums.
Based on the behavior you're seeing, it may be worth focusing on how the modem or DHCP process is handling connected device MAC addresses rather than signal or provisioning issues. Since internet access and the modem's local status page both stop working when a different MAC is connected, the issue may be occurring before a public IP address is assigned.
You may want to verify whether the working MAC is the original hardware MAC and possibly perform a factory reset of the modem, and continue to test with a device connected directly to the modem.
(And apologies to @EG for repeating already sage advice!)
(edited)
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EG
Expert
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120K Messages
3 hours ago
@XfinityCliff Darn echoes...
@user_3zero824wzz Did you get a chance to try that factory reset ?
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