If there is an index.html or index.htm or a variant of these files inside of the directory, the web server won't let you browse through directories.

If I redirect “/index.html” to “/”, will this allow browsing of my website directories because it no longer has a page titled “/index.html” or does the page it is redirected to www.sample.com/ serve as the index page?

In other words, will it expose my directories that would normally be directed to the index page or will my website directories be protected because the "www.sample.com/" page will become the index?