Go to: Account → 2-Step Verification → Enable
When you enable this option, we send you a code (either in an e-mail or in a text message). You must use this code to verify your current IP.
Every time you log in from a new IP, we send you a new code that you must use to verify the new IP.
If you add new IPs manually, we will send you a code that you need to use in order to verify the new IP.
If you enable the Two-Step Verification you will get a new code each time a new IP is trying to access your account and when you are trying to add a new IP manually.