404 meaning and reason of not found

404 not found? Why does 404 not found appear?

404 meaning of not found:

404 not found is a standard HTTP return code. When a user inputs a link, the IIS (Internet Information Service) on the server) the system first checks whether the URL you entered has the corresponding webpage information. If there is no webpage information, it indicates that the user entered an invalid link, at this time, IIS will send a 404 error code page prompt to the end user through the server, telling the user that the webpage information corresponding to the address link cannot be found. In the Chinese web page environment, if the 404 return page is optimized in Chinese and reasonably, the user will be notified of his input error in the first time, and the user will be directed to the correct link through the optimized 404 page, instead of leaving the website immediately, we can say that the appearance of 404 not found greatly improves the user experience and is more friendly to users.

404 not found reason:

First, the address link entered by the user is incorrect, causing IIS to prompt 404 not found.

Type 2: the current page on the server has been deleted. This issue occurs frequently in BBS forums. Posts posted N years ago are now searched by the search engine, however, in fact, in order to ensure the proper use of server resources, BBS forums will delete expired or very old information pages, resulting in 404 not found.

Third, DNS settings are blocked. In the Chinese environment, some banned websites in foreign countries will also see 404 not found during browsing in China, which requires the use of proxy servers for normal browsing.

From a professional perspective, there are only three reasons:

1. You cannot access the Web site on the requested port.

2. The Web service extended locking policy blocks this request.

3. The MIME ing policy blocks this request.

In short, the 404 not found error page is intended only to prompt the user to guide the user, rather than the fault. It can kindly prompt that the user page cannot be accessed.