Block Specific IP Addresses from Accessing Your Site

add_action( 'init', 'wpfolks_block_bad_ips' );
function wpfolks_block_bad_ips() {
    $blocked_ips = [
        '192.168.1.100',
        '203.0.113.45',
        // Add more IPs here
    ];

    $visitor_ip = $_SERVER['REMOTE_ADDR'] ?? '';

    if ( in_array( $visitor_ip, $blocked_ips, true ) ) {
        wp_die(
            'Access denied.',
            'Forbidden',
            [ 'response' => 403 ]
        );
    }
}