A robots.txt file lives at the root of your site. Learn how to create a robots.txt file, see examples, and explore robots.txt rules.| Google for Developers
This document specifies and extends the "Robots Exclusion Protocol" method originally defined by Martijn Koster in 1994 for service owners to control how content served by their services may be accessed, if at all, by automatic clients known as crawlers. Specifically, it adds definition language for the protocol, instructions for handling errors, and instructions for caching.| www.rfc-editor.org