HOw to use "Client ID to send when requesting DHCP" with xfinity


The Xfinity Modem in US, usually talks to only one "mac address" if one has to switch routers behind the modem, you have to call them and have them "re-provision" the device, basically PITA, but I was able to use the "force macaddr" on the WAN side to get around this.

THe the most recent version of openwrt 23.05 this has been apparently replaced by "Client ID to send when requesting DHCP" and I have no clue as to how this works.

Anyone here has any experience or can explain ?


The client ID is not necessary or relevant here.

You have two options:

  1. Restart the modem, maybe several times, to clear the old MAC association and allow it to learn a new MAC


  1. Clone the old router's MAC address into the new router.

Usually, #1 is the easiest. You may even find that you need to disconnect power from the modem for 10-30 minutes, but usually a restart or few will fix the issue.

Disconnect power from both devices and leave it for a minute or two. Connect the ethernet cable between the cable modem and the OpenWrt WAN port. Then, power on the cable modem and allow it to boot fully. Once that has completed, power-up the router and see where things stand. It should usually work, but if that doesn't work, power repeat the process but power cycle the cable modem 2 or 3 times before powering on the router.


Its the netgear CM1200 which I have

Anyone have experience with this particular one here ?

My question is how do I do 2 in the latest stable OpenWRT

There is no option

in the older versions we used to have this...

(see the 2nd to last option, they seem to have removed it :frowning: )


MAC address is not the same thing as client ID. Though by default DHCP clients often derive the client ID from the MAC address, they are two completely different bit fields in the packet that is sent to the modem.

To change the MAC address edit the Device (eth port) which is connected to the modem, and change it there. Go to the Network Interfaces page and note the device name (it is in the bottom of the corresponding box on the left, and it is usually wan on a DSA kernel). Then go back to the top of the list and click the Devices tab and find the device in the list and click Configure. There there is a box to enter an override MAC address.