In order to increase your site’s protection, Sucuri offers an extra layer of protection to Sucuri Firewall users.
It is what we call Protected Pages.
This option allows you to restrict access to certain pages on your site and it can also be used as a secondary authentication on your admin panels.
This is what site visitors will see:
Two Factor Authentication with Google Authenticator
IP Address Restriction
To enable the protected page you may refer to this link [link].