Site notifications
Från MoodleDocs
Location: Administration > Security > Notifications
Display login failures to
It is probably necessary to dispay login failures to administrators only if people are attempting to steal student or teacher logins. The administrator is the administrator with the lowest id in the user-table (= the first created and still active administrator), all administrators are all users with the administrator role
Email login failures
If you're concerned about login failures, you can set up email notification for administrators.
Threshold for email notifications
This sets the number of failed logins for a given user from a single computer that will trigger notification.