The WP-Backend is secured by an IP Blocker.
Can I define IP ranges? Not exactly but you can enter sth like '192.168..' or '...666' or '' (free for all) * is used as a Wildcard.
I entered the wrong IP adress and can't enter the backend anymore, what can I do? You have no chance to log in again, so the best way to get back to it, is to rename the plugin. So the plugin is inactive and you can login again.