404 not found meaning

404 not found is a status code returned by HTTP for web page errors. When the user enters a URL in the browser, the server will determine whether there is corresponding web page information based on the entered address. If there is no corresponding information, it means that the user may have entered a series of invalid links, and the server will return a 404 not found status code to the user, telling the user that the corresponding web page information was not found.

Usually a 404 not found prompt appears on a website, which is to tell website users that this page does not exist and has not been found. (Recommended learning: PHP video tutorial)

Cause of occurrence

Normal website if there is no revision or other special operations There will be no 404 not found problem. If the problem occurs, it is very simple. Maybe your website has abnormal operations. The main reasons for 404 not found are as follows:

1. The website has been revised, such as It is said that the website program is changed, the database is not correct, etc., so many web content may not be found, that is, dead links. Another example is that when a website changes servers, some static files are not copied to the new server, or the files do not have read permissions due to folder permission issues on the new server, so a 404 not found problem occurs.

2. If the website is hacked and some or all files on the website are lost, a 404 not found error page will also appear. This situation is relatively rare.

3. Deleting a certain directory will result in a 404 not found error page prompt. For example, an article was manually deleted due to copyright issues, but has been included by search engines. When a user searches for this article and opens it, a 404 error message will appear.

4. Due to dynamic rule changes, it is also common for the 404 not found error to appear on the page. When a dynamic page changes due to pseudo-static rules, the URL may change, and the previous URL will be invalid. When we open the previous URL after the rule change, a 404 not found error message will naturally appear. [2]

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

6. DNS settings are blocked. As far as the Chinese environment is concerned, some banned foreign websites will also display the 404 not found phenomenon when browsing in China. This requires the use of a proxy server to browse normally.

Function and impact

Function:

It is quite necessary for the website to set up a 404not found page. It can improve the user experience of the website, and secondly, it can help reduce user churn.

Impact:

1. If the website has too many 404 error pages, the search engine will think that the website is being revised or is being maliciously attacked, and will demote the website. Process and wait for recovery to increase the weight of the website.

2. When a user opens a website and clicks on a link, an error page appears. The same problem still occurs when clicking on the second link. This is not conducive to the user experience. Users may think that the site is a spam website, resulting in many links being opened. If not enabled, it will increase the bounce rate of the website.

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