Changing router MAC address causing internet to stop working after new cable modem installation

Question

I used to change my MAC address in my router configuration all the time in the past. However, I recently upgraded with my ISP and they installed a new cable modem. What I normally do is modify the last digit of the MAC address (to an allowable character of course), and then unplug my modem and router. Since the new modem installation though, the internet doesn't work after I do that. After changing the last digit of the address back to the original one, it works again. Is there something in the upgrade that's restricting me from changing it or something?

My router is a Cisco Linksys E3200 and my modem is a Cisco DPQ3212. My ISP is Cox.

Thank you.

Solution

Does your modem have a backup battery? You may need to use a reset button on the modem to truly reset it.

It's possible the cable modem may have recorded the MAC address of your router in its NVRAM, or your ISP has recorded it, and you will need to call them to tell them to clear it.

Comments

[STTR]

Describe the clearer the connection diagram. What you are doing. Connect directly? Connect devices to each other? Only installing Cisco Linksys E3200?

[Marcel Waldvogel]

Please describe which component does what (NAT, …). BTW: Why do you want to modify the MAC address anyway?

[Ramhound]

Cox registered the MAC address to avoid certain actions by their customers they decided was not worth doing. You will have to contact COX and tell them the new mac address of the modem.