Cascaded network unable to access default gateway att 5031nv

Question

Hello -  I have a Cisco 3750 sitting behind an ATT 5031 NV.  The Cisco device has the following networks 'living' on it: 10.1.1.1 /2410.1.2.1 /2410.1.3.1 /24 All of these have DHCP pools living on the Cisco device.  The default gateway they had out is the IP of the SVI (mentioned above).  I am using OSPF between those networks - and they can all talk fine.  I am using the 'default-information originate' command to obtain default route information. I have port Gi1/0/3 on the cisco device plugged into LAN port 4 on the ATT 5031 NV.  Port Gi 1/0/3 is configured with a static IP in the 192.168.1.x network as follows:
ip address 192.168.1.2 255.255.255.0 On the ATT 5031 NV:  Settings > broadband > link configuration, I have the 'cascaded network' option selected: Network Address:  10.1.0.0 Subnet Mask:  255.255.0.0 Choose the router that will host the secondary subnet:          [Cisco Device Hostname] 192.168.1.2 (IP of Gi1/0/3 on cisco device) When i do this - i can ping from the 10.x.x.x networks to both 192.168.1.2 and 192.168.1.254 IP's - but i cannot get out to the Internet (neither by IP or hostname).   I should metion that I have tried the DMZ pinhole option - where i made my Gi1/0/3 get an IP by DHCP > rebooted it > and I got my device to show up with a 108.225.x.x external IP (which again, my 10.x.x.x's could ping) but I could not ping the default gateway for that network. What am i missing here?  anyone have any ideas?  Config to follow:  !interface GigabitEthernet1/0/3
description DMZ to WAN
no switchport
ip address 192.168.1.2 255.255.255.0!interface Vlan1
no ip address
interface Vlan100
description MANAGEMENT
ip address 10.1.1.1 255.255.255.0
interface Vlan120
description xxxx WIFI
ip address 10.1.2.1 255.255.255.0
interface Vlan130
description xxxx DATA
ip address 10.1.3.1 255.255.255.0!router ospf 1
network 10.1.1.0 0.0.0.255 area 1
network 10.1.2.0 0.0.0.255 area 1
network 10.1.3.0 0.0.0.255 area 1
default-information originate!ip default-gateway 192.168.1.254!ip route 0.0.0.0 0.0.0.0 192.168.1.254 Any help would be greatly appricated.     

Answer 1

Hi ,
With the cascaded router option, the purpose of that option is to pass over your static IPs so that your gateway handles the traffic. If you do have a set of static IPs available, the only thing you want to change is the cascaded router IP. The network address should be the IP of your router, so it would be 192.168.1.2 according to your setup. 
If you are just trying to do a router behind router setup, you actually do not need to use the cascaded router option, and just putting it in DMZ should take care of everything.
Hope this helps.
-ATTU-verseCare