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


What is Duo Mobile?

Auburn University uses Duo Security to prompt individuals for a secondary confirmation of their identity at log in using a physical device in their possession. This process is called multi-factor authentication, or MFA. The physical device may be a smartphone or tablet using an app, a text message to a phone, an automated voice call to landlines or cell phones, or a hardware token.

AU employees and students are strongly encouraged to register a least two alternative devices, such as a smartphone or cell phone number (as a landline) or a tablet.

Why Do I Need Duo Mobile?

Duo Mobile is a security requirement for AU employees and students. Duo Mobile uses multi-factor authentication to confirm your identity when accessing certain university resources.

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

Once you have registered for Duo Mobile, there are various methods and device types that can be used when authenticating. Listed below are instructions for using Duo on an iPhone, Android, cellular phone, or landline.

Note: To use the Duo Mobile Passcode authentication method, the minimum requirements for the Duo Mobile app are iOS 15 or Android 11, and the Duo Mobile app should be version 4.49 or later. For instructions on updating your app to the most current version available, see the Knowledge Base article How to Update Apps on iOS and Android Devices.   

For the iPhone and Android device types below, you will find information on the following:

You can also use Duo with any cellular phone or landline. Below, you will find instructions on the following:

Below, you will also find instructions for choosing a different authentication method 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 the Duo Mobile app installed on an iPhone, you can authenticate using a Duo Push or Duo Mobile Passcode, even without an internet connection or cellular service.

The latest version of the Duo Mobile app can be found in the Apple App Store. As of February 22, 2024, iOS 15.0 is the minimum-supported version for Duo Mobile

Duo Push Authentication Method on an iPhone:

Duo Push is the easiest and quickest way of authenticating. When logging into a resource requiring Duo, you will see a prompt showing that a Duo Push has been sent to your phone, as shown in the first image below. Simultaneously, you will receive a login request sent to your phone, as shown in the second image below. 

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

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

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

Duo Mobile Passcode Authentication Method on an iPhone:

If you do not have an internet connection or cannot get cellular service, you can still use a Duo mobile passcode to authenticate. The passcode is always available but will appear hidden.

Note: To use the Duo Mobile Passcode authentication method, the minimum requirements for the Duo Mobile app are iOS 15 or Android 11, and the Duo Mobile app should be version 4.49 or later. For instructions on updating your app to the most current version available, see the Knowledge Base article How to Update Apps on iOS and Android Devices.   

When logging into a resource requiring Duo, you will see a prompt asking you to enter your Duo mobile passcode, as shown in the image below.

Duo mobile passcode 

To obtain a Duo mobile passcode, open your Duo app on your iPhone, and locate the account that you need a passcode for (some users may have two accounts). When you locate the account, tap Show to display the six-digit passcode.

iOS Duo passcode screen

You will see the Duo mobile passcode displayed. Duo mobile passcodes expire and auto-refresh after 30 seconds, as noted in the timer bar below the passcode. If the 30 second timer runs out, a new Duo mobile passcode will display.

Duo mobile passcode

Enter the Duo mobile passcode from the app into the prompt, and select Verify to complete the authentication.

Duo mobile passcode

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:

Check for authentication requests by pulling the account list down in the Duo Mobile app. Duo Mobile automatically checks for authentication requests, but if you think you have missed a request, open the app and pull down to refresh.

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 the Duo Mobile app installed on an Android, you can authenticate using a Duo Push or Duo Mobile Passcode, 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 easiest and quickest way of authenticating. When logging into a resource requiring Duo, you will see a prompt showing that a Duo Push has been sent to your phone, as shown in the first image below. Simultaneously, you will receive a login request sent to your phone, as shown in the second image below.

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

Duo Mobile Passcode Authentication Method on an Android:

If you do not have an internet connection or cannot get cellular service, you can still use a Duo mobile passcode to authenticate. The passcode is always available but will appear hidden. 

When logging into a resource requiring Duo, you will see a prompt asking you to enter your Duo mobile passcode, as shown in the image below.

Duo mobile passcode

To obtain a Duo passcode, open your Duo app, and locate the account that you need a passcode for (some users may have two accounts). When you locate the account, tap Show to display the six-digit passcode.

Duo show passcode option on Android

You will see the Duo mobile passcode displayed. Duo mobile passcodes expire and auto-refresh after 30 seconds, as noted in the timer bar below the passcode. If the 30 second timer runs out, a new Duo mobile passcode will display.

Duo mobile passcode

Enter the Duo mobile passcode from the app into the prompt, and select Verify to complete the authentication.

Duo mobile passcode

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:

Check for authentication requests by pulling the account list down in the Duo Mobile app. Duo Mobile automatically checks for authentication requests, but if you think you have missed a request, open the app and pull down to refresh.

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.

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, you can still 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 ever want 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.

Duo authentication options

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