SEO Literacy HTTP status code

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As SEO, often look at the site's log, the site log has a lot of code, often see 200, 404, 503 And so on, these numbers are the HTTP status code. As

61.135.166.232--[31/dec/2007:02:30:11 +0800] "get/category21.html http/1.1 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 18395"-"" mozilla/5.0 (compatible; googlebot/2.1; +http://www.google.com/bot.html) "

When a user or search engine's robot (robot) or crawler (crawler) opens (or crawls) a page of your site, the request is sent to your server, and the server gives an HTTP status code to respond to the request.

This status code provides information about the status of the request, telling the search engine about your site and the requested page. Search engines use HTTP status Codes to identify page status, such as telling a search engine that the page exists or does not exist or is an error link.

Common HTTP status codes are:

200-The server successfully returned to the Web page

404-The requested Web page does not exist

503-The server is temporarily unavailable

When you look at the Web site's log, you often encounter the code, you can use this code to understand some of the site. To facilitate viewing and casual understanding of the representative meaning of the relevant HTTP status code, a complete list of HTTP status codes is provided below. Click on the link to learn more. You can also access the WWW page on the HTTP status code to get more information.

1XX (Temporary response)

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

Code description

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.

2XX (Success)

Represents the status code that successfully processed the request.

Code description

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

201 (created) request succeeded 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 successfully processed the request, but the information returned 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.

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 Web crawl page under Diagnostics lists URLs that are Googlebot unable to crawl due to redirection errors.

Code description

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 for subsequent requests. This code, like the 301 code in response to a GET or 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 requestor last requested it, you should configure the server to return this response (called the If-modified-since HTTP header). Because the server can tell Googlebot that the page has not changed since the last crawl, it can save 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 for subsequent 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.

4xx (Request error)

These status codes indicate a possible error in the request and hinder the processing of the server.

Code description

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 Web pages that need to log on.

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 be denying Googlebot access.

404 (Not found) the server cannot 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 robots.txt files on your site and you see this status on the robots.txt page of the Google Webmaster Tools Diagnostics tab, this is the correct state. However, if you have a robots.txt file and you see this state, your robots.txt file may be named incorrectly or in the wrong place (the file should be in the top-level domain name, robots.txt).

If you see this state (on the HTTP error page of the Diagnostics tab) for the URL that Googlebot is trying to crawl, it means that the Googlebot trace may be an invalid link for another page (an old link or an incorrect 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 (unauthorized), but the specified requester should authorize the use of the agent. If the server returns this response, it also indicates the agent that the requester should use.

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. The server may return this code in response to a put request that conflicts with the previous request, along with a two-request difference list.

410 (Deleted) If the requested resource has been permanently deleted, the server returns this response. The code is similar to the 404 (not Found) code, but is sometimes substituted for 404 code in cases where the resource existed before and is not present. If the resource has been permanently deleted, 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 scope, the server returns this status code.

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

5XX (server error)

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

Code description

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.

Author: SEO Fang

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