Hi everyone,
I recently installied a linksys MODEM DPC3008 for Comcast cable internet. I can get internet if I have my laptop directly wired to modem.
But if I add a router (RB750Gr2) connected to the modem , there is no internet.

I logged on to the 750, and found the router didn't get WAN IP address, gateway, etc., although I choose "automatic" under IP address acquired.

The router is set to router mode instead of bridge mode. I changed router to 3011, it is same. As long as you put the router inbetween,you don't get internet. But you can always get online if you connect directly to modem.

Any suggestion will be highly appreciated !

Thanks !

Did you reboot the cable modem each time you change connections? The cable modem "learns" the MAC address of the first device it sees on boot.

Hi everyone,
I recently installied a linksys MODEM DPC3008 for Comcast cable internet. I can get internet if I have my laptop directly wired to modem.
But if I add a router (RB750Gr2) connected to the modem , there is no internet.

I logged on to the 750, and found the router didn't get WAN IP address, gateway, etc., although I choose "automatic" under IP address acquired.

The router is set to router mode instead of bridge mode. I changed router to 3011, it is same. As long as you put the router inbetween,you don't get internet. But you can always get online if you connect directly to modem.

Any suggestion will be highly appreciated !

Thanks !

In addition to what IntrusDave mentioned, how is your route configured? You mention it is in "router mode." Where is your computer connected to if the 750 is connected to the modem? What network exists for the computers within your network? Is there a NAT configured?

Further, you mention that you have it selected for "automatic" are you referring to DHCP? What port is set as your WAN port on the 750? Is that port the one the cable connects to between your 750 and the modem?

I've had this problem in the past and I had to change the mac address on the interface of my Mikrotik connected to the cable modem.
Change the mac, restart the modem and make sure you have DHCP client set to the correct interface.