Getting NETGEAR Cable Modem Gateway CG3000D-2 to coexist with FRITZ!Box 7270

Posted on 2013-11-25
Last Modified: 2013-12-02
Hi Experts,

I have been running a FRITZ!Box 7270 as an ADSL modem, router etc.

I have just added a NETGEAR Cable Modem Gateway CG3000D-2 (because I have switched from ADSL to cable Broadband).
It's on a different subnet (192.168.0.x) to the FRITZ!Box (192.168.1.x)

These are the LAN Settings for the NETGEAR:
LAN IP Address:
Subnet Mask: 255.255.255.       
DHCP Server:  No  (was Yes, but I want to change it to No, so that the FRITZ!Box does DHCP)

I have tried changing the settings to:

LAN IP Address:
Subnet Mask: 255.255.255.       
DHCP Server:  No

But when I click the Apply button, I get this error:

"LAN IP address and Guest LAN IP can't be in the same subnet"

What's the "Guest LAN IP"?

Question by:LeighWardle
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Expert Comment

by:Dave Baldwin
ID: 39676925
Each of those devices wants to 'own' the network it is connected to.  Putting one on a different subnet will not help.  They would have to be completely physically different networks.  

I actually have that setup here with DSL and Cable.  I have several computers with two NIC cards, one connected to each device.  They have to be setup so that only one of them has a 'gateway' defined because Windows will just get confused if you enable the gateways on both of them.

Accepted Solution

LeighWardle earned 0 total points
ID: 39682643
Thanks, Dave, for your comments.

I did get it work, here's how:

Changed Fritz!Box Home Network | Network | Network Settings | IPv4 addresses:
IPv4 address:
enable DHCP Server range: - 200

See User Manual, Section 5.2:
Fritz!Box Internet | Account Information | Internet Service Provider | choose "Existing Connection over LAN"

connected Cat5 cable from Fritz!box LAN 1 to cable modem

All working now!


Author Closing Comment

ID: 39689475
I solved the problem myself.

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