301, 404, 200, 304, 500, etc. http status, what does the representative mean?

Some common status codes are :

200-The server successfully returned to the Web page

404-The requested Web page does not exist

503-Server Timeout

The complete list of HTTP status codes is provided below. Click on the link to learn more details. You can also access the WWW page on the HTTP status code to get more information.

I. Interim response

1XX (Temporary response)

A status code that represents a temporary response and requires the requester to continue to perform the operation.

100 (continued) The requester should continue to make the request. The server returns this code indicating that the first part of the request has been received and is waiting for the remainder.

101 (switching protocol) The requestor has asked the server to switch protocols, and the server has confirmed and is ready to switch.

Second, Success

2XX (Success)

Indicates that the requested status code was successfully processed.

200 (successful) the server has successfully processed the request. Typically, this indicates that the server has provided the requested Web page. If this status code is displayed for your robots.txt file, it means that Googlebot has successfully retrieved the file.

201 (created) The request was successful and the server created a new resource.

202 (accepted) the server has accepted the request but has not yet processed it.

203 (non-authoritative information) the server has successfully processed the request, but the returned information may be from another source.

204 (no content) the server successfully processed the request but did not return any content.

205 (reset content) the server successfully processed the request but did not return any content. Unlike the 204 response, this response requires that the requester reset the document view (for example, clear the contents of the form to enter new content).

206 (partial content) the server successfully processed a partial GET request.

Third, redirect

3xx (redirect)

Further action is required to complete the request. Typically, these status codes are used for redirection. Google recommends that you do not use redirects more than 5 times per request. You can use webmaster tools to see if Googlebot is having problems crawling the redirected Web page. The network crawl page under Diagnostics lists URLs that Googlebot cannot crawl due to redirection errors.

300 (multiple choices) for a request, the server can perform a variety of operations. The server can select an action based on the requester (user agent) or provide an action list for the requester to choose from.

301 (permanently moved) The requested page has been permanently moved to the new location. When the server returns this response (a response to a GET or head request), the requestor is automatically transferred to the new location. You should use this code to tell Googlebot that a Web page or Web site has been permanently moved to a new location.

302 (Temporary mobile) The server is currently responding to requests from Web pages in different locations, but the requester should continue to use the original location to respond to future requests. This code, like the 301 code in response to a get and head request, automatically moves the requester to a different location, but you should not use this code to tell Googlebot that a Web page or Web site has moved because Googlebot will continue to crawl the original location and index it.

303 (View other locations) The server returns this code when the requester should use a separate GET request to retrieve the response for a different location. For all requests except the head, the server automatically transfers to a different location.

304 (not modified) The requested page has not been modified since the last request. When the server returns this response, the content of the Web page is not returned.

If the Web page has not changed since the last request from the requestor, you should configure the server to return this response (called the If-modified-since HTTP header). The server can tell Googlebot that the page has not changed since the last crawl, thus saving bandwidth and overhead.

.

305 (using a proxy) the requester can only use the proxy to access the requested Web page. If the server returns this response, it also indicates that the requester should use the proxy.

307 (temporary redirection) The server is currently responding to requests from Web pages in different locations, but the requester should continue to use the original location to respond to future requests. This code, like the 301 code in response to a get and head request, automatically moves the requester to a different location, but you should not use this code to tell Googlebot that a page or Web site has moved because Googlebot will continue to crawl the original location and index it.

four, request error

4xx (Request error)

These status codes indicate that the request may be wrong and hinder the processing of the server.

400 (Error request) The server does not understand the syntax of the request.

401 (not authorized) request authentication. The server may return this response for a Web page that is requested after logging in.

403 (Prohibited) the server refused the request. If you see this status code when Googlebot tries to crawl a valid page on your site (you can see this information on the Web crawl page under Google Webmaster Tools Diagnostics), your server or host may have denied Googlebot access.

404 (Not found) the server could not find the requested Web page. For example, this code is often returned for pages that do not exist on the server.

If you do not have a robots.txt file on your site and you see this status code on the robots.txt page of the Google Webmaster Tools Diagnostics tab, this is the correct status code. However, if you have a robots.txt file and you see this status code, your robots.txt file may be named incorrectly or in the wrong place (the file should be in the top-level domain, named robots.txt).

If you see this status code (on the HTTP error page of the Diagnostics tab) for a Googlebot crawl URL, it means that Googlebot is following an invalid link for another page (either an old link or an incorrectly typed link).

405 (method Disabled) Disables the method specified in the request.

406 (not accepted) cannot use the requested content attribute to respond to the requested Web page.

407 (proxy authorization required) This status code is similar to 401 (not authorized), but the specified requester should authorize the use of the agent. If the server returns this response, it also indicates that the requester should use the proxy.

408 (Request timed out) timeout occurs when the server waits for a request.

409 (conflicting) the server encountered a conflict while completing the request. The server must contain information about the conflict in the response. This code may be returned by the server in response to a put request that conflicts with the previous request, as well as a two-request difference list.

410 (Deleted) If the requested resource has been permanently deleted, the server returns this response. This code is similar to the 404 (not Found) code, but is sometimes substituted for 404 code in cases where the resource existed before and now does not exist. If the resource is moved permanently, you should use 301 to specify a new location for the resource.

411 (requires a valid length) the server does not accept requests that do not contain a valid content Length header field.

412 (Prerequisites not met) the server did not meet one of the prerequisites that the requester set in the request.

413 (Request entity too Large) the server was unable to process the request because the request entity was too large to handle the server.

414 (The requested URI is too long) The requested URI (usually the URL) is too long for the server to process.

415 (Unsupported media type) The requested format is not supported by the requested page.

416 (Request range does not meet the requirements) if the page cannot provide the requested range, the server returns this status code.

417 (expectations not met) the server did not meet the requirements for the "expected" Request header field.

　　

v. Server Errors

5XX (server error)

These status codes indicate that the server encountered an internal error while processing the request. These errors may be errors on the server itself, not the request.

500 (server internal error) the server encountered an error and could not complete the request.

501 (not yet implemented) the server does not have the capability to complete the request. For example, this code may be returned when the server does not recognize the request method.

502 (Error Gateway) The server received an invalid response from the upstream server as a gateway or proxy.

503 (Service Unavailable) the server is not currently available (due to overloading or downtime maintenance). Usually, this is only a temporary state.

504 (Gateway Timeout) The server acts as a gateway or proxy, but does not receive requests from upstream servers in a timely manner.

505 (HTTP version is not supported) the server does not support the HTTP protocol version used in the request.