A robots.txt is a text file created by a webmaster to show how to crawl through pages on his website.
If you do not want a search engine or bot to crawl through certain pages of your site, a robots.txt file can be useful to give instructions to search engines and bots. When they crawl through a website, they can read it to know which pages to deal with and which to avoid.
If you want to block a certain user agent, you must remember that the bot must follow the rules set out in your robots.txt file. Technically, the robots.txt is not an obligation to follow guidelines, but it is a guide for web crawlers.
Search engine bots look for the robots.txt in your website. If you don’t want to instruct a search bot how to search your web pages, you don’t need a robots.txt file.
The most common directive used for robots is disallow, which tells the robots.txt not to access the url path. If you are a web server administrator and do not want your bot to visit other sites, you can use the robots.txt file to specify where the bot should go and where not.
The user-agent directive is used in robots.txt files to specify that the crawler should follow certain rules.
Although Googlebot and other reputable web crawlers follow the instructions in robots.txt files, other crawlers cannot. Some bots could interpret the statement differently from the user-agent.
Not all web robots follow these instructions, and some even use the robots.txt to find prohibited links and get directly to them. Also remember that robots.txt files are not your legal guardian and that bots do not have to obey the robots.txt. Some bots do not even bother to search for the files and simply search the entire website. A malicious web bot is unlikely to honor a robots.txt. The robots.txt file is designed only as a guide for the web bots.
If you don’t have a robots.txt file, search engine robots (like Googlebot) will have easy and complete access to your website.
If you don’t know if your website has a robots.txt file, you can visit any website adding /robots.txt after the domain.
It is good practice to add a Robots.txt file that allows easy and complete access to all the robots on your website (search engine robots, web crawlers and other web robots).
The Robots.txt file is a simple text file that is placed on your web server root directory.
The robots.txt file has been used to limit server load for bots, spiders and other crawlers. Today Googlebot self regulates its crawling activities.