Duo: Methods of Using Duo on an iPhone, Android, Cellular Phone, or Landline


What is Duo Mobile?

Auburn University uses Duo Security for multi-factor authentication (MFA) to verify identity during login using a physical device. The physical device may be a smartphone or tablet using the Duo Mobile app, a text message to a cell phone, an automated voice call to a landline or cell phone, or a Duo hardware token. Users are encouraged to register at least two devices for backup. The Duo Mobile app is the recommended method for multi-factor authentication. 

Why Duo Mobile Is Needed

Duo Mobile is a security requirement for Auburn University employees and students. Duo Mobile uses MFA to confirm your identity when accessing certain university resources. 

Duo Mobile Minimum Requirements

Applications/Resources Requiring Duo Mobile

This is a partial list of software utilized by Auburn and whether it is protected by VPN or Duo MFA.

VPN Required:

MFA Required (VPN is NOT Required):

Auburn Credentials Required (VPN and Duo MFA Not Required):


Methods of Using Duo on an iPhone, Android, Cellular Phone, or Landline

After registering for Duo Mobile, you can authenticate using different methods on various devices, including iPhone devices, Android devices, cellular phones, and landlines.

For iPhone and Android, the instructions below cover:

For cellular phones and landlines, the instructions below cover:

Additionally, guidance is provided below for selecting alternative authentication methods using the Duo Universal Prompt.


Using Duo Mobile on an iPhone Using Duo Mobile on an Android Using Duo with any Cellular Phone or Landline Choosing a Different Authentication Method

Using Duo Mobile on an iPhone


With Duo Mobile installed on an iPhone, you can authenticate using the Duo Push method, even without an internet connection or cellular service.

The latest version of the Duo Mobile app can be found in the Apple App Store. Starting February 17, 2025, iOS 16 will be the minimum supported version for Duo Mobile.

Duo Push Authentication Method on an iPhone:

Duo Push is the recommended authetication method, sending a login request to your phone when you attempt to access a Duo-protected Auburn resource.  

Duo push notification

Tap Approve to successfully authenticate. If you receive a push request that you were not expecting, press Deny in order to reject the request. You will be given the ability to report it as fraudulent.

Duo push on iOS device

You can respond to Duo pushes from a Duo banner notification on your iOS lock screen or home screen.

From your lock screen, simply tapping the Duo banner notification will open the Duo push for you to approve.

Duo push on iOS lock screen

You can also tap and hold the Duo banner notification and receive the option to either Approve or Deny the push.

Duo push on iOS lock screen with approve or deny option

From your home screen, you can swipe down on the Duo banner notification to either Approve or Deny the push.

Duo push on iOS home screen with swipe down to approve or deny

If the Duo Mobile prompt is not displaying correctly (for example, the Duo prompt is an outlined, grey box or a white screen), this may be related to content restriction settings on your iOS device. Refer to the Knowledge Base article: Duo: Resolving Duo Prompt Display Issues Related to iOS Content Restrictions for steps to fix this issue.

Adding Accounts to Duo Mobile on an iPhone:

Some users may need to add additional accounts to Duo. During the Duo setup process, you will see a barcode to scan.

To add a new account:

1. Open the Duo app from your iOS device and tap Add (plus icon in upper right).

Add Duo account on iOS device

2. Tap Use QR code. Scan the barcode to link your account to Duo Mobile.

Duo add account use QR code on iOS device

3. After scanning the QR code, you will be given the option to rename your Duo account if you prefer. Select Save, and the Duo account will be linked to your iPhone.

Duo account saved on iOS device

Removing Accounts from Duo Mobile on an iPhone:

To remove an account from Duo, find the account you wish to remove in the Duo Mobile app. Tap the three dots in the upper right of the screen, and tap Delete.

remove Duo account in iOS

Refreshing the Duo App on an iPhone:

To check for Duo authentication requests, open the Duo Mobile app and pull down to refresh the account list.  Duo Mobile automatically checks for  requests, but manual refresh ensures none are missed.

Your Duo Mobile account information is backed up automatically when you enable iCloud Backup on your phone, and this backup can be restored only on the same device. The iCloud backup cannot be used to migrate your Duo accounts to a new phone. For more information, see Apple's guide to enabling iCloud backup.

Using Duo Mobile on an Android


With Duo Mobile installed on an Android, you can authenticate using the Duo Push method, even without an internet connection or cellular service.

The latest version of the Duo Mobile app can be found in the Google Play Store. As of February 8, 2024, Android 11 is the minimum-supported version for Duo Mobile. 

Duo Push Authentication Method on an Android:

Duo Push is the recommended authentication method, sending a login request to your phone when you attempt to access a Duo-protected Auburn resource.

Duo push notification

Tap Approve to successfully authenticate. If you receive a push request that you were not expecting, press Deny in order to reject the request. You will be given the ability to report it as fraudulent. 

Duo push on an Android device

You can respond to Duo pushes from a Duo banner notification on your Android lock screen or home screen.

From your lock or home screen, tap on Tap To View Actions on the Duo banner notification.

Duo push banner notification on Android

You can then select Deny or Approve in the Duo banner notification. If you choose Deny, you will be given the ability to report it as fraudulent.

Duo deny or approve push on Android

Adding Accounts to Duo Mobile on an Android:

Some users may need to add additional accounts to Duo. During the Duo setup process, you will see a barcode to scan.

1. To add a new account, open the Duo app from your Android device and tap Add (plus icon in upper right).

Add account in Duo app on Android

2. Tap Use QR code. Scan the barcode to link your account to Duo Mobile.

QR code for Duo new account on Android

3. After scanning the QR code, you will be given the option to rename your Duo account if you prefer. Select Save, and the Duo account will be linked to your Android.

Duo save account on an Android

Removing Accounts from Duo Mobile on an Android:

To remove an account from Duo, find the account you wish to remove in the Duo Mobile app. Tap the three dots in the upper right of the screen, and then tap Delete.

Duo remove account on Android

Refreshing the Duo App on an Android:

To check for Duo authentication requests, open the Duo Mobile app and pull down to refresh the account list.  Duo Mobile automatically checks for  requests, but manual refresh ensures none are missed. 

Information on backing up and restoring your registered Duo Mobile accounts on an Android device can be found in this Duo Knowledge Base article.

Using Duo with any Cellular Phone or Landline


Duo works with all cell phones and landlines by supporting authentication via phone call and SMS passcodes, as long as you have cellular data access on the phone.

Follow the instructions below on how to utilize the Duo Phone Call and SMS Text Passcode authentication methods.

Duo Phone Call Authentication Method:

When logging into a resource requiring Duo, you will see a prompt directing you to, "Answer the phone call; verify it's you by pressing 7 on your phone." 

Duo phone call option

Simultaneously, you will receive a phone call on the cellular phone or landline that you have registered in Duo. The phone caller ID will display that it is coming from the Auburn OIT Service Desk at (334) 844-4944. Answer the call, listen to the instructions to authenticate, and press 7.

After pressing 7 on your phone device, you will see a success notification on your screen, indicating the completion of the phone call authentication process.

Duo SMS Text Passcode Authentication Method:

If you do not have an internet connection, but have cellular data access, you can use a text passcode from Duo in order to authenticate. 

When logging into a resource requiring Duo, you will see a prompt directing you to, "Enter your passcode; verify it's you by entering the passcode sent in a text to your phone device." 

Duo text passcode prompt

Simultaneously, a passcode will be texted to the phone that you have registered for Duo authentication.

Enter the text passcode in the Duo prompt, and select Verify to complete the authentication. 

Duo prompt passcode screen

After selecting Verify, you will see a success notification on your screen, indicating the completion of the text passcode authentication process. You can also select Send a new passcode to generate a new passcode via text. A new text passcode will invalidate all previous text passcodes.

Choosing a Different Authentication Method


If you need to choose a different device or Duo authentication method than the one chosen automatically by the Duo Universal Prompt, or want to cancel an authentication in progress to select a different method, select Other options near the bottom of the Duo Universal Prompt. 

Duo other options selection

This takes you to a list of all your available Duo authentication options. Select the method you want to use, and follow the prompt instructions shown to complete logging into the resource or application. (Note: Duo Mobile passcodes are no longer an option; only Duo Pushes, phone calls, SMS text messages, or Duo Token codes, if needed.)

Duo authentication options

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