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.

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EG

Expert

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120K Messages

3 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.

XfinityCliff

Official Employee

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513 Messages

1 day 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)

EG

Expert

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120K Messages

1 day ago

@XfinityCliff Darn echoes...

@user_3zero824wzz Did you get a chance to try that factory reset ?

user_3zero824wzz

Visitor

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2 Messages

@EG I would like to thank you and the xfinityCliff for your information. It's helped me to make the decision that I'm not going to attempt to address my problem right now.

Because:

- The first thing I would have to do is do a factory reset of the modem. Then I'm definately offline.

- Second, I would try to use the xfinity app to reprovision my modem. But my modem is no longer on the xfinity compatibiliy list so I think there is a good likelyhood that the reprovisioning would not work and I would get a message that my modem is not on the compatibilty list.

- Third, if I called Xfinity support and they tried to reprovision it, their ability to do so would also be unsuccessful because they would not have the option availble for my old modem.

- Forth, and this is the kicker: Even if I then bought a new modem and got it up and running, I still might not be able to change my IP address by changing the MAC address because Xfinity just might be locking down connections to single MAC addresses. I have other information that xfinity has been doing this for the past couple years and as old xfinity components are updated in xfinity's IT systems, the new components are stricter and locking down connections is a security measure.

So I think I'll just wait and use my system the way it is until my Arris modem someday bites the dust.

Thanks for your input.

10 hours ago

XfinityJamesC

Official Employee

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3.1K Messages

Thank you for clearing that up, @user_3zero824wzz. As far as I know, the only restriction we have in place for a retired modem like the SB6183 is that we can no longer activate it. We should still be able to perform standard troubleshooting steps like restarting or reprovisioning it, although reprovisioning an EOL (end of life) modem like the SB6183 is not advisable. Even if it was successful, it probably wouldn't end up changing your IP address anyway. Please let us know if you have any questions or encounter any other issues. Our amazing community is always ready to help.

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10 hours ago

EG

Expert

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120K Messages

5 hours ago

@user_3zero824wzz

Understood, especially if it and that router are delivering your current speed tier needs. They want all DOCSIS 3 (and lower) off of their systems sooner rather than later, so one day it may just cease to function. You're prolonging the agony IMO. Good luck !

BTW, I have not heard or seen anything about any changes in the way that their system handles MAC addy binding.

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user_3zero824wzz

Lost ability to change WAN IP address by changing MAC address. Can only get internet with a specific MAC address.

EG

XfinityCliff

EG

user_3zero824wzz

XfinityJamesC

EG

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