Can't get Linksys router with Ambit modem to work

Hi everyone!

Perhaps this is an easy question but I just can't get this to work.  I have a customer who has the Time Warner basic road runner service.  She is connected to the Internet via an Ambit modem (model #U10C018).  Connected directly to the modem, the Internet connection works fine but when I put a linksys router (WRT54GL) in between, I just can't get internet.  Here are the things I've tried:

*Rebooting both the modem and the router.
*turning off the modem and router and waiting quit a bit of time before I turn them back on again.
*cloning the computer's MAC address.

I talked with tech support and they said there are no restrictions on sharing the internet connection in our area.  Also, I check in the router under STATUS and it seems to be picking up the IP address, DNS and gateway.  There is no firewall installed currently on the computer except for the Windows firewall.  No Norton Internet security or anything like that.  Router is set to obtain everything automatically.  HELP!   I won't be back at the customer's until Saturday afternoon so I'll get back to you all after then after I implement all your suggestions.  Thanks for your help in advance.
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JFrederick29Connect With a Mentor Commented:
You rebooted the PC also right so it picked up the new DHCP information from the Linksys?  I would do an "ipconfig /all" on the PC to make sure it is receiving a correct IP address from the Linksys along with the correct default gateway and DNS servers (the same as the Linksys learned) from the ISP.

Make sure you can ping the Linksys from the PC and try to ping websites on the Internet by name and IP address.
Rob WilliamsConnect With a Mentor Commented:
A long shot:
What WAN IP does the Linksys get ? (if posting only post the first 2 octets like 123.123.x.x) I noticed the U10C020 (not your unit) is also a combined router. If either because the modem is also performing NAT or the service providers is doing so, and you receive an IP in the 192.168.1.x subnet, you will have a conflict with the default LAN side subnet on the Linksys, which defaults to  If this is the case change the LAN side IP of the router to something like

Another possibility is you may have a connection but not be receiving the DNS server's IP through DHCP from the router. To test try going to:  (this is goggle in IP form)
If this works try adding the ISP's DNS server (found on the router's status page) to the DHCP configuration for the LAN client machines.
herrbradshawAuthor Commented:

Here's what it was.  Unbelievably, the Linksys Router was bad.  Although I was able to ping it, I noticed that it wasn't sending out a  wireless ID that my laptop could pick up.  In addition, the lights were blinking in an unusual manner.  I switched out the router with a Belkin wireless and VOILA, it worked.  Thanks to the both of you for responding.  Your ideas were good and I will use them next time for troubleshooting.  I'm splitting the points between you.  Thanks for your time.

Chris :)
Rob WilliamsCommented:
Thanks herrbradshaw, glad to hear you resolved.
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