What do the HTTP status codes in website logs mean? What does it mean?

Friends who do website SEO optimization know that in order to do a good job in website optimization and ranking, learning to read website log analysis is essential, and now there are many website log analysis tools, such as: Lagerhao, Light Year Log Analysis, etc. However, a lot of the data in it makes us unable to understand and feel very confused. How should I look at it? Today editor Dongguan SEO Feng Chao will share it with you. What do the HTTP status codes in website logs represent and mean?

What do the HTTP status codes in website logs mean? What does it mean?

When doing SEO, we often see code like this in the log:

61.135.166.232 - - [31/Dec/2007:02:30:11 +0800] "GET /category21.html HTTP/1.1" 200 10968 "-" "Baiduspider+(+http://www.baidu.com/search/spider.htm)"
66.249.70.172 - - [31/Dec/2007:03:36:10 +0800] "GET /32_10_zh.html HTTP/1.1" 200 18395 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
What you need to know here is the strange number "200" (the other number represents the size of the file being captured).
"200" is the HTTP status code.
The most common HTTP status codes in the SEO process are:
200 - The server successfully returned the web page
404 - The requested page does not exist
503 - Server Timeout

Other commonly encountered HTTP status codes are listed below:

HTTP Status Code Summary Description Success 2×× Status code indicating that the request was successfully processed.
200 The server has successfully processed the request and provided the requested web page.
204 The server successfully processed the request but did not return any content.
Redirect 3×× Do not use more than 5 redirects in each request.
301 The requested page has been permanently moved to a new location. When URLs change, use the 301 code. Save the new URL in the search engine index.
302 The requested web page has been temporarily moved to a new location. The original URL is saved in the search engine index.
304 If a web page has not been updated since the last request by the requester, the 304 code is used to tell the search engine robot, saving bandwidth and overhead.
Client error 4×× indicates that there may be an error in the request that prevented the server from processing it.
400 The server did not understand the syntax of the request.
403 The server rejected the request.
404 The server cannot find the requested page. This code is often returned by a webpage that does not exist on the server.
410 The server returns this response after the requested resource has been permanently deleted. This code is similar to the 404 (Not Found) code, but is sometimes used instead of the 404 code when the resource previously existed and no longer exists. If the resource has been permanently deleted, you should use 301 to specify the new location of the resource.
Server error 5×× indicates that an internal error occurred on the server while processing the request. These errors may be errors with the server itself, rather than errors with the request.
500 The server encountered an error and could not complete the request.
503 The server is currently unavailable (either because it is overloaded or down for maintenance). Usually, this is only a temporary condition.
These are just the HTTP status codes that are commonly encountered in SEO. If you want to learn more, you can go to Dongguan SEO Feng Chao’s blog to learn more.