If for whatever reason you want to return the plugin to default settings - as if you had just installed it for the first time - you can currently only do this with FTP access.
A UI will be created for this later, but the purpose of this is to handle scenarios where you enable a setting that locks you out.
- Connect to your site's web hosting space using FTP or any file manager
- Browse to the plugin's folder: ..../wp-content/plugins/wp-simple-firewall/
- Under the 'wp-simple-firewall' folder there will be folder called 'flags'
- Create a new file in this directory called: reset
- This file should have no extension, not other letters or characters. It isn't reset.php, reset.html, or anything like that - just 'reset'
- Reload your site and settings will have returned to defaults.