HTTP protocol error Code Encyclopedia

The error code, also known as the status code, refers to the 3-digit code allocated for each request (Web click) received by the server. Most valid page clicks have status code 200 ("normal"). The "Web page not found" error produces a 404 error. Some common code is shown in bold. 1xx (Temporary response)

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

Code description

100 (continued) The requester should continue to make the request. The return of this code by the server means that the server has received the first part of the request and is now waiting to receive the remainder.

101 (switching protocol) The requestor has asked the server to switch the protocol, and the server has confirmed and is ready to switch. 2xx (Success)

Used to indicate that the server has successfully processed the requested status code.

Code description

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

201 (created) The request was successful and the server has 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 returned information that might 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 the requester to reset the document view (for example, to clear the contents of the form to enter new content).

206 (partial content) the server successfully processed a partial GET request. 3xx (redirected)

To complete the request, you need to do it further. Typically, these status codes are always redirected. Google recommends that you use fewer than 5 redirects per request. You can use webmaster tools to see if Googlebot is having problems crawling your redirected Web page. The crawl error page under Diagnostics lists URLs that Googlebot cannot crawl due to redirection errors.

Code description

300 (multiple selections) the server can perform multiple operations on request. 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 (as a response to a GET or head request), the requestor is automatically transferred to the new location. You should use this code to notify Googlebot that a Web page or Web site has been permanently moved to a new location.

302 (Temporary move) 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. However, since Googlebot will continue to crawl and index existing locations, you should not use this code to notify Googlebot that a page or Web site has been moved.

303 (View other locations) The server returns this code when the requester should make a separate GET request to retrieve the response in a different location. For all requests except the head request, 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, the server also indicates the agent that the requester should use.

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. However, since Googlebot will continue to crawl and index existing locations, you should not use this code to notify Googlebot that a page or Web site has been moved. 4xx (Request error)

These status codes indicate that the request may have been faulted and that the server has been prevented from processing the request.

Code description

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

401 (not authorized) request for authentication. After logging in, the server may return this response to the page.

403 (disabled) the server refused the request. If this status code is displayed when Googlebot tries to crawl a valid page on your site (you can see this status code on the Web crawl page that is diagnosed in Google webmaster tools), this may be your server or host denying Googlebot access to it.

404 (Not found) the server could not find the requested Web page. For example, if the request is for a page that does not exist on the server, the server typically returns this code.

If you do not have robots.txt files on your site and you find 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 find this state, it means that your robots.txt file may be a named error or in the wrong place. (This file should be located on the top-level domain name and should be named Robots.txt).

If you find this status on the Web site that Googlebot is trying to crawl (on the HTTP error page of the Diagnostics tab), this means that Googlebot is tracking an invalid link in another page (an old link or an incorrectly typed link).

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

406 (not accepted) The requested content attribute cannot be used to respond to the requested Web page.

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

408 (Request timeout) the server timed out waiting for the request.

409 (conflicting) the server encountered a conflict while completing the request. The server must contain information about the conflicts that occurred in the response. The server may return this code when responding to a put request that conflicts with the previous request, while providing 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 it sometimes replaces 404 code when the resource has existed before but is no longer present. If the resource has been permanently deleted, you should specify a new location for the resource using the 301 code.

411 (requires a valid length) the server will not accept requests that contain invalid content-Length header fields.

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 and exceeded the server's processing power.

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 request is for an invalid range of Web pages, the server returns this status code.

417 (expectations not met) the server did not meet the requirements for the "expected" 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, the server might return this code when the request method is not recognized by the server.

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

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, as a gateway or proxy, did not receive requests from the upstream server in a timely manner.

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