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Log in Using a Phone Callback for Two-Step Login

How to use a phone call to authenticate with Two-Step Login

This article applies to: Two-Step Login

With the Phone Callback method, Two-Step Login calls you on your mobile phone or landline.

To authenticate:

  1. When you're prompted with the Two-Step Login screen, click Call Me.
  2. Answer the phone call.
  3. When you hear the automated "Welcome to Cornell Two-Step Login" greeting, press the requested number key on your phone to authenticate.  To find the number:
    • Press the number shown in the authentication prompt on your computer screen:


    • For a phone with Caller ID, the number you need to press appears as the last digit of the incoming phone number. For example, if Caller ID displays 607-253-3333, press 3 on your phone keypad to log in;

    • Listen to the phone message and press the requested number on your phone.
Voice/SMS calls from Duo usually display a Caller ID from an on-campus Cornell phone number. Occasionally a Duo call may come from an off-campus phone number elsewhere in the United States. If you just tried to log in and are expecting a Duo call, the call is probably legitimate.
If you think this is a fraudulent login attempt, press # to report it to a security engineer.

For more information, see Duo Security's Guide to Two-Factor Authentication.

Support Contact:

Cornell IT Service Desk

Normal Business Hours: Monday-Friday, 8am-6pm (Eastern Time)
Emergency Service Disruptions: After Hours Support


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