• Jesus Lucio

AT&T Modem to Sonicwall Device

Finally, the real truth on how to set your AT&T modem into a dumb device!


Here is the list of hardware I have:

Sonicwall router/firewall Motorola NVG589 16 port switch (managed, but that shouldn’t make a difference)


Things you will need:

MAC address from your personal router CAT5 cable Patience (*key ingredient)


Let’s begin, first steps

This will involve you having a computer connected to your U-verse router, this should be the only cable plugged in to the router at this point.

Let’s configure some settings on the U-verse router:

  • Navigate to your U-verse default ip, usually 192.168.1.254

  • Go to ‘Home Network’ then ‘Subnets & DHCP’. You will be asked to enter the password to the router, this is found on the side of the device.

  • Make sure the “Device IPv4 Address” is not in the same subnet as your personal router, if it is, you need to change it. For example, if they are both 192.168.1.254, change the U-verse to 192.168.2.254.

  • You can change the “DHCPv4 Start and End Address” if you would like, I did not. This just limits the U-verse router to assign IP’s and possibly broadcasting. These addresses are mainly used by the TV’s and the wireless extenders for your TV’s.

  • Click “SAVE”

  • Go to ‘Home Network’ then ‘Wireless’ and turn wireless off. No need to have this on if you are going to be using your own, this will just cause interference with other WIFI signals.

  • Go to ‘Firewall’ then ‘ ‘Packet Filter’. Disable Packet Filters. You will be using your own on the personal router.

  • Go to ‘NAT/Gaming’ and make sure there is nothing configured. There should’t be, but just make sure.

  • Go to ‘Firewall’ then ‘IP Passthrough’

  • For ‘Allocation Mode’ choose ‘Passthrough’

  • The ‘Passthrough Mode’ choose ‘DHCPS-Fixed’

  • Type the MAC address of your personal router in the box under ‘Manual Entry’.

  • Click ‘SAVE’, the router will tell you to reboot, don’t do it yet.

  • Go to ‘Firewall Advanced’ and turn everything off and SAVE

  • Now you can reboot the router, this will take about 2 minutes to complete.

Final steps, personal router settings:

  • You can now unplug your computer and plug it into your personal router and log in. Typically, default IP address is 192.168.1.1

  • Since my setup involved an more advanced router (Sonicwall), it was a little different. The setup should be the same for most routers.

  • Find the area where you configure the WAN settings.

  • The WAN settings should be configured for Dynamic or Automatic IP. Once the personal router is configured, the U-verse router will give the external public IP to your personal router. (*Note and check your WAN settings on your firewall and should have the Public IP of your AT&T that you were given.)

  • ‘Enable WAN’, ‘Enable NAT’ and ‘Enable UPnP’

  • Consider changing your DNS addresses to something more reliable, like Google’s or OpenDNS.

  • Reboot your router and check to make sure everything is configured correctly by going to the Internet.


This configuration will differ from your setup, but the concept is the same. Basically, I wanted to pass everything from the U-verse to my setup and allow all my public facing clients to still work.












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