Use Duo Code Authentication for VPN Duo has several forms of authentication available, one of which is a Duo Code Authentication. In the Duo app on your phone, you can generate a 6-digit code that can be used to login. This method can be used with or without a connection to cellular data or WiFi. Please refer to the following steps in order to use a Duo code with VPN: Go to vpn.marquette.edu to download the Marquette VPN client. After the client has been installed, launch the VPN client and enter vpn.marquette.edu in the portal address field. When prompted for log in credentials, in the Username field, enter your Marquette username. In the Password field, enter your password followed by a comma. An example of this would be: MyPassword, Go to the Duo mobile app on your registered device and tap Show next to the Passcode. On your device, a 6-digit passcode will appear. Enter that 6-digit code into the password field next to what was entered in Step 3. Click Connect and you will be connected to Marquette VPN.