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How to connect your Cisco RV120W Router to ATTs 2Wire 3801HGV DSL Modem


How to connect your Cisco RV120W Router to ATTs 2Wire 3801HGV DSL Modem

Below are the instructions. Impossible to get it to work with ATTs tech support so you will have to do it yourself:


Part #1 - Modem Configuration

-Connect the LAN cable to your computer

-Access the 3801HGV Modem Admin interface by typing: in your browser (try Internet Explorer)

-Select  Settings>Firewall>Applications, Pinholes and DMZ>Select your Router (Something such as unknown00B56D03B206) > 

- Click on "Allow all applications (DMZplus mode) ......" 

- Click on "Save" button below



- Go to Settings>Firewall>Advance Configuration

- Type your password (if you don't have one use the one that is on a stamp on your modem next to "Device Access Code")

- Uncheck: Stealth Mode, Block Ping, Strict UDP Session Control

- Check all under: Outbound Protocol Control except for NetBIOS

- Uncheck all under Inbout Protocol Control (or just NetBIOS under this submenu)

- Uncheck all under Attack Detection

Then Restart your modem and try to access the internet with your computer not your router.


A new screen will show up asking you to Restore or Decline Router-to-Router fixes. Type your password and click on "Decline". If you don't see this screen your cisco router will not be able to access the Internet (keep reading if this happens).

Part #2 - Router Configuration

- Now connect your Cisco router to the LAN of your Modem

- Run the setup wizard on your router otherwise Access the admin pannel under your Cisco Router under in your browser

- To see if you have network access try Administration>Diagnostics>Network Tools then type on IP Address/Domain Name. The Click on ping. If you get a response then you have access. 

- Type If this works then you are connected. If not, your modem might still be blocking your access or you cannot resolve a domain name.

- Go to Networking>LAN (Local Network)>IPv4 LAN (Local Network)>Primary DNS Server and type and then on Secondary DNS Server

- Restart both Modem and Router (modem first then router)

- Try again. If this doesn’t work go to your modem (not your router) admin page again into Settings>System Info>Even Notifications and click next to "Router-Behind-Router Detection".

If you restart both (modem and router) and you still can't Ping or access the Internet, repeat Part 1 above once you are sure "Router-Behind-Router Detection" is enabled.

If you still can't access the internet try changing the MAC address of the router. Go into Networking>IPv4 WAN (Internet)>MAC Address Source and select "Use This Computer's Address".

-Restart the modem and you should be all set

No one at ATT will be able to help you and most of the issues are from the ATT Modem not the Cisco Router(s).


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Community Manager

Re: How to connect your Cisco RV120W Router to ATTs 2Wire 3801HGV DSL Modem



Thank you for taking your time to put this tutorial together! I'm sure some users will find it very useful.



Rethink Possible

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