Customize whether a request is blocked in Shield

functions.php

<?php declare( strict_types=1 );

/**
 * Use this filter to tell Shield to block a request.
 *
 * By default, Shield will block requests solely based on the IP reputation for that site.
 *
 * With this filter, you can change these criteria.
 * 
 * In this example we want to block all access to the WP admin and WP login areas and
 * restrict it to only IP addresses found on the IP Bypass list. We have to be careful
 * to not block access to AJAX.
 */
add_filter( 'shield/is_request_blocked', function ( $isBlocked ) {

	// $isBlocked defaults to true if the IP is blocked by Shield. False otherwise.
	if ( !$isBlocked && !is_ajax() && \Shield\get_ip_state() !== 'bypass' ) {
		$isBlocked = is_admin() ||
					 \FernleafSystems\Wordpress\Services\Services::WpGeneral()->isLoginUrl();
	}

	// ALWAYS return $isBlocked.
	return $isBlocked;
} );