Crawling and indexing are different operations. Choose the control that matches the intended outcome instead of blocking pages indiscriminately.
Choose the intended outcome
Robots.txt manages crawler access to paths. Noindex tells supporting search engines not to index a resource when they can read the directive. A blocked URL may still be known through links. Private information needs access control; neither file should be treated as authentication.
Avoid contradictory settings
If a crawler cannot fetch a page, it cannot see that page’s noindex directive. Review HTTP headers as well as HTML settings. Keep excluded pages out of the public sitemap. Test a specific URL and its actual response rather than assuming a CMS checkbox affects every file type.
Verify changes carefully
Inspect important production pages after modifying rules. Keep a copy of the previous configuration for recovery. Search tools may take time to reflect a change, so distinguish delayed reporting from a wrong live setting. Investigate the response seen by the crawler before repeatedly altering directives.