You must have a data or wireless internet connection in order to receive a push. However, with the Duo Mobile app on your phone, you can tap the green key button to receive a 6-digit passcode.
This option will work even without an internet connection and/or cellular service.
If you are outside the U.S. and receiving the message below when using Duo, see this article about OFAC-countries/regions.
“Access denied. Duo Security does not provide services in your current location”
2FA with the Cisco Secure Client VPN
On the Cisco Secure Client VPN, you will type this information into the password field on Cisco Secure Client VPN.
For example: password,725495
2FA with Web Apps
On the 2FA page, you will select Enter a Passcode and type the passcode from the Duo Mobile app.