
Nicole Cozma/CNET
Many companies across the Web are providing support for secondary authentication. Some do this with apps like Google Authenticator, while others just use SMS. Essentially, both methods provide you with a security code that you need to provide in order to log-in to your account.
LinkedIn is currently offering SMS authentication only, and you’ll need to enable it. Here’s how to set it up:

Nicole Cozma/CNET
- Open the top-right menu and click on Manage next to Privacy & Settings.

Nicole Cozma/CNET
- On the tabs along the bottom-left-hand side, click Account > Manage security settings (bottom of the left column).

Nicole Cozma/CNET
- Under Two-step verification for sign-in, click Turn On. Enter a reliable cell phone number and then click Send Code.
Enter the code you receive via SMS to log back in to the LinkedIn website.
Editors’ note, June 12, 2015: This How To post was originally published on May 31, 2013, and has been updated to include new information.