Linksys Router Doesn’t Connect to Ambit uBee U10C018 Cable Modem

I recently ran into a situation where a Linksys WRT-54G wasn’t able to get an IP address when connected to an Ambit/uBee U10C018 cable modem. This issue may also apply to other routers when used with the U10C018 cable modem.

When a PC is connected directly to the modem, everything works fine and the Internet can be reached normally. When a router is placed inbetween, then there is no longer any access to the Internet. Viewing the status information in the router shows that it is unable to acquire an IP address, even though the router is set to use automatic configuration via DHCP, the same as the PC.

Apparently, the U10C018 cable modem is aware of the MAC address of various routers. In order to get the router to work with the modem, use the MAC cloning feature of the router. The location of this option will depend on your particular router brand and model. When you find it, turn it on. Then, set the desired MAC address.

On the Linksys router, the MAC address cloning page has a button to copy the MAC from the PC that’s currently connected to the administration interface. If your router has this feature, use it to set the router to the same MAC address as your computer. If your router does not have this feature, then you’ll have to get your MAC from the network driver or the network card.

Once you have a non-router MAC entered into the MAC cloning setting, save and restart the router.

Have you run into this issue? If so, post your router model and steps to configure MAC cloning for it in the comments.

17 thoughts on “Linksys Router Doesn’t Connect to Ambit uBee U10C018 Cable Modem”

  1. My Model Number Is: Linksys BEFW11S4
    To configure mac cloning: enter router setup, select Mac Address Cloning and select clone.

    This does not work for me.

  2. @David: Cloning didn’t work? Does the modem work properly when you connect your computer directly to it?

  3. I just ran into a similar situation with a different Ubee cable modem … but the problem is on the cable bonding side, not the modem. Hidden in my ISP support pages it says “the IP address is internally associated with the MAC address. If you remove the PC then attach a router, you MUST power cycle both the modem and the router for a new association”.

    Original poster? did you power off/on both devices? Try it.

  4. @Random Reader: Yes, tried power-cycling multiple times. Apparently, that one didn’t want to re-associate. Good tip, though. Could help others with their model of cable modem. Thanks!

    I’ve also heard of cases where turning on the router before the modem will get them to cooperate.

  5. I have a Belkin F5D8235-4 and it also would not associate an IP address from the modem. Cloning fixed the problem though.
    Setup > Manual > Internet Wan > MAC Address Cloning > Clone

  6. It seems like you can reset the MAC address the modem recognizes first by disconnected any ethernet conenected device. Then either reset it to factory defaults, then plug it into the Router, or power cycle it, then plug it into the router.
    See if this works. Usually works for me when i have these issues. simpler than making changes in Router Settings.

  7. UBee U10C018 cable modem D-Link DIR-655 Home network.

    Directly connected PC to UBee modem first and this worked.

    Did not have to clone PC MAC to router *BUT* did have to power cycle UBee modem _after_ D-Link DIR-655 router’s internet connection method was changed to Dynamic-IP-DHCP.

    Cloning the MAC address of the PC to the router may also work but I did not try this and I think power cycling the modem _after_ the router is an easier way to try first. Just make sure the router is setup for Dynamic-IP or Static-IP (if you have asked for one from your provider).

  8. ” If you remove the PC then attach a router, you MUST power cycle both the modem and the router for a new association”.
    This approach worked for me.
    UBee U10C018 cable modem and Linksys WRT54G router

  9. Linksys WRT54G firmware v1.02.8

    Cloning works excellent. This was with my Comcast Ubee D3.0.

    Thanks, OP!

  10. Thanks for this tip! I have a WRT300N with this Comcast modem and doing the MAC cloning made it work!

  11. i had this problem, linksys router not working with Ubee modem. I called Time warner, they said i had to call Linksys..Linksys said they would help me for a fee of $29.99 !!!..I have not tried to resolve the issue, i have just done without wireless. so this info may be a huge help for me. Although, i may not able to do these steps without help. i am going to give it a try,,thanks for the postings !!!

  12. My router will not connect to the internet called time warner they were not able to help me. I called linksys and they wanted to charge me 30 bucks. Still no connection I cant even access the settings page. So frustrating.

  13. Elsa: Try connecting your computer directly to the cable modem and get that working first. The cable company should be able to help you with that. Cable companies often won’t deal with a router that they did not install. Once you get your computer working directly with the cable modem, then connect the router back and investigate that knowing that the modem and cable line are functioning. You don’t want to have too many unknowns at the same time when debugging.

  14. Modem did not work by itself so I thought I had a bad one even though it was new right out of the box. Just skipped that part and went on with the rest of the steps, worked the first time.
    Thank you very much