After you have installed the extension, you must configure it. You can find the Security settings under Theme My Login → Security.
Throttling & Lockout
This section contains the settings for controlling login throttling and lockout. The settings are outlined below.
Enter the number of failed login attempts you wish to allow before locking out an IP address.
This is the amount of time the above defined attempts must occur in before lockout occurs.
This is the amount of time an IP address it locked out once the above threshold is breached with the defined number of attempts.
Check "Immediately lockout invalid usernames" to lock out any IP address who enters a username which does not exist.