以下是过滤器的建议：

/**
 * Filters a comment\'s approval status before it is set.
 *
 * @since 2.1.0
 * @since 4.9.0 Returning a WP_Error value from the filter will shortcircuit comment insertion and
 *              allow skipping further processing.
 *
 * @param bool|string|WP_Error $approved    The approval status. Accepts 1, 0, \'spam\' or WP_Error.
 * @param array                $commentdata Comment data.
 */
$approved = apply_filters( \'pre_comment_approved\', $approved, $commentdata );

add_filter( \'pre_comment_approved\', function( $approved, $commentdata ) {
    $domain = substr( strrchr( $commentdata[\'comment_author_email\'], \'@\' ), 1 );
    $banned_domains = [
        \'example.com\',
        \'example.org\',
        \'example.net\',
        \'localhost\'
    ];
    if ( in_array( $domain, $banned_domains ) ) {
        wp_die( __( \'Please use a real email!\' ) );
        //return new WP_Error( \'comment_real_email\', __( \'Please use a real email!\' ) );
    }
    return $approved;
}, 10, 2 );

另一个较早触发的是：

/**
 * Filters a comment\'s data before it is sanitized and inserted into the database.
 *
 * @since 1.5.0
 *
 * @param array $commentdata Comment data.
 */
$commentdata = apply_filters( \'preprocess_comment\', $commentdata );