Updated
I've got a Motorola SBG900 cable modem sitting in front of a Linksys WRT54G running DD-WRT. The DHCP server is running on the Linksys router not the modem.
I can access the DD-WRT web GUI via the router's IP address but can not access the modem's web GUI without connecting directly to it.
What configuration is necessary to be able to access the modem's web GUI when connected to the router.
Here's the setup:
- Modem's IP: 10.0.0.1
- Router's WAN IP: 10.0.0.2
- Router's Internal IP: 10.0.0.3 (Gateway IP used by computers connected to the router):
- Both the router and the modem are on
the same subnet (255.255.255.0). - The ethernet cable from the
modem is connected to the WAN port on the router. - Originally I believe only the router
was running a DHCP server. Since the
modem was recently reset, I believe
it may be running a DHCP server now
as well. It's hard to tell since I
can't access it's GUI remotely. 🙂
Best Answer
As heavyd said, the address for the modem needs to be on a different subnet than the one controlled by your router.
Just to clarify, the subnet mask shows which part of the IP address is the subnet. A subnet mask of 255.255.255.0 means the first three numbers in the IP address are the subnet.
So in your setup, both the router and the modem have the subnet 10.0.0.x. When you enter the address 10.0.0.1, the router sees that address is on the subnet it controls and never sends packets for that address out on its WAN port.
So, as heavyd said, the solution is to change the router's IP address to any private IP address that doesn't begin with 10.0.0.
For example, you could change your router's IP address to 10.3.3.3 and leave its subnet mask at 255.255.255.0. In that case the router's subnet would be 10.3.3.x. Then when you enter the address 10.0.0.1, the router will see that address isn't on the subnet it controls and will send packets for that address onward to its WAN port.