Our forum threads have the URL format /category/threads/123. Each post within a forum thread has a permalink URL /category/threads/123/1 and /category/threads/123/2, which jump to the specific post on the page. Regardless of which URL you use, I am setting the canonical URL to /category/threads/123. Should I also set the meta robots tag to noindex when the URL is the permalink for a specific post? Or is setting the canonical good enough?