How do I authenticate using text messaging (SMS)?
Enroll your device as a cell phone
In order to authenticate using text messaging (SMS), you must first first enroll your device as a mobile phone. When Duo asks you what type of device you have ("My device is a...") be sure to select Other (and cell phones).
Authenticate Using SMS
- When authenticating, Duo will prompt you to "Choose an authentication method." If you have more than one device enrolled, you will see a device selector - be sure to select your mobile phone. On this screen select Enter a Passcode.
- A blue bar will appear on the bottom of the Duo window. Click on the Send codes button to have Duo text you a batch of passcodes. The blue bar will confirm that the codes have been sent to you.
- To authenticate using an SMS passcode, click the Enter a Passcode button, type in a passcode you received from Duo via text message, and click Log In.
Duo keeps track of which SMS passcodes you've already used in your batch, letting you know which one to use next.
You can have new passcodes sent to you at any time. A new batch of passcodes will invalidate all old passcodes, so it is recommended that you delete the old text message when a new one comes in.
More information can be found in Duo's documentation: