The Shield Security plugin is composed of the several modules. The IP Manager is one of its modules. This module allows you to whitelist IP addresses and configure auto-blacklist rules.

You can access this module from within Shield plugin main dashboard (under the Settings tab):

IP Manager module is designed of the following parts (features):

Note: "Request Tracking" and "User Messages" options are available with Shield Pro only. To find out what the extra features for Shield Pro are, read the article here.

Before you take any action, you should carefully review the automatic black list settings. 

The Automatic IP Black List system settings

The IP Manager module's main part is the Automatic IP Black List system (engine). It tracks bad behavior over a set period of time and as soon as it reaches the threshold, the Shield blocks it. No more lengthy and unmaintainable IP black lists.

To set-up the Automatic IP Black List system, use the following options:

For more information, read the blog article here.