HTTP Status Codes: Tutorial and Course

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HTTP Status Codes Tutorial and HTTP Status Codes Course


HTTP Status Codes: Overview


HTTP Status Codes Tutorial and Course - HTTP Status Codes tutorial and HTTP Status Codes course, the ultimate guide to HTTP Status Codes, including facts and information about HTTP Status Codes. HTTP Status Codes Tutorial and Course is one of the ultimate created by to help you learn and understand HTTP Status Codes and the related SEO technologies, as well as facts and information about HTTP Status Codes.



HTTP Status Codes Tutorial, HTTP Status Codes Course

HTTP Status Codes: Tutorial and Course - HTTP Status Codes Tutorial and HTTP Status Codes Course by , The Ultimate Guide to HTTP Status Codes.



HTTP Status Codes: Tutorial and Course




HTTP Status Codes: Overview


What is HTTP Status Codes

According to , HTTP Status Codes is Hypertext Transfer Protocol (HTTP) Response Status Codes, which includes codes from Internet Engineering Task Force (IETF) internet standards as well as other IETF RFCs, other specifications and some additional commonly used codes. The first digit of the HTTP status codes specify one of five classes of response; the bare minimum for an HTTP client is that it recognises these five classes. The phrases used are the standard examples, but any human-readable alternative can be provided. Unless otherwise stated, the HTTP status codes are part of the HTTP/1.1 standard (RFC 2616).



HTTP Status Codes: Facts and Information


Facts and Information about HTTP Status Codes

The official registry of HTTP status codes are maintained by the Internet Assigned Numbers Authority (IANA).



HTTP Status Codes: 1xx Informational


The HTTP status codes 1xx indicate a provisional response, consisting only of the Status-Line and optional headers, and are terminated by an empty line. The HTTP status codes 1xx mean that request received, continuing process. Since HTTP/1.0 did not define any 1xx HTTP status codes, servers must not send a 1xx response to an HTTP/1.0 client except under experimental conditions.





HTTP Status Code: 100 Continue

HTTP status code 100 means that the server has received the request headers, and that the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). If the request body is large, sending it to a server when a request has already been rejected based upon inappropriate headers is inefficient. To have a server check if the request could be accepted based on the request's headers alone, a client must send Expect: 100-continue as a header in its initial request and check if a 100 Continue status code is received in response before continuing (or receive 417 Expectation Failed and not continue).



HTTP Status Code: 101 Switching Protocols

HTTP Status Code 101 means that the requester has asked the server to switch protocols and the server is acknowledging that it will do so.



HTTP Status Code: 102 Processing (WebDAV; RFC 2518)

HTTP Status Code 101 means that as a WebDAV request may contain many sub-requests involving file operations, it may take a long time to complete the request. This code indicates that the server has received and is processing the request, but no response is available yet. This prevents the client from timing out and assuming the request was lost.



HTTP Status Codes: 2xx Success


The HTTP Status Codes indicate the action requested by the client was received, understood, accepted and processed successfully.





HTTP Status Code: 200 OK

The HTTP Status Code 200 means that standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request the response will contain an entity describing or containing the result of the action.



HTTP Status Code: 201 Created

The HTTP Status Code 201 means that the request has been fulfilled and resulted in a new resource being created.



HTTP Status Code: 202 Accepted

The HTTP Status Code 202 means that the request has been accepted for processing, but the processing has not been completed. The request might or might not eventually be acted upon, as it might be disallowed when processing actually takes place.



HTTP Status Code: 203 Non-Authoritative Information (Since HTTP/1.1)

The HTTP Status Code 203 means that the server successfully processed the request, but is returning information that may be from another source.



HTTP Status Code: 204 No Content

The HTTP Status Code 204 means that the server successfully processed the request, but is not returning any content.



HTTP Status Code: 205 Reset Content

The HTTP Status Code 205 means that the server successfully processed the request, but is not returning any content. Unlike a 204 response, this response requires that the requester reset the document view.



HTTP Status Code: 206 Partial Content

The HTTP Status Code 206 means that the server is delivering only part of the resource due to a range header sent by the client. The range header is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.



HTTP Status Code: 207 Multi-Status (WebDAV; RFC 4918)

The HTTP Status Code 207 means that the message body that follows is an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.



HTTP Status Code: 208 Already Reported (WebDAV; RFC 5842)

The HTTP Status Code 208 means that the members of a DAV binding have already been enumerated in a previous reply to this request, and are not being included again.



HTTP Status Code: 226 IM Used (RFC 3229)

The HTTP Status Code 226 means that the server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.



HTTP Status Codes: 3xx Redirection


HTTP Status Codes 3xx means that the client must take additional action to complete the request. This class of status codes indicate that further action needs to be taken by the user agent in order to fulfil the request. The action required may be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A user agent should not automatically redirect a request more than five times, since such redirections usually indicate an infinite loop.





HTTP Status Code: 300 Multiple Choices

The HTTP Status Code 300 indicates multiple options for the resource that the client may follow. It, for instance, could be used to present different format options for video, list files with different extensions, or word sense disambiguation.



HTTP Status Code: 301 Moved Permanently

The HTTP Status Code 301 means that this and all future requests should be directed to the given URI. For more information about 301 Moved Permanently, please visit .



HTTP Status Code: 302 Found

The HTTP Status Code 302 means that this is an example of industry practice contradicting the standard. The HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect (the original describing phrase was "Moved Temporarily"), but popular browsers implemented 302 with the functionality of a 303 See Other. Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours. However, some Web applications and frameworks use the 302 status code as if it were the 303.



HTTP Status Code: 303 See Other (Since HTTP/1.1)

The HTTP Status Code 303 means that the response to the request can be found under another URI using a GET method. When received in response to a POST (or PUT/DELETE), it should be assumed that the server has received the data and the redirect should be issued with a separate GET message.



HTTP Status Code: 304 Not Modified

The HTTP Status Code 304 indicates that the resource has not been modified since last requested. Typically, the HTTP client provides a header like the If-Modified-Since header to provide a time against which to compare. Using this saves bandwidth and reprocessing on both the server and client, as only the header data must be sent and received in comparison to the entirety of the page being re-processed by the server, then sent again using more bandwidth of the server and client.



HTTP Status Code: 305 Use Proxy (Since HTTP/1.1)

The HTTP Status Code 305 indicates that many HTTP clients (such as Google Chrome, Mozilla Firefox, and Internet Explorer) do not correctly handle responses with this status code, primarily for security reasons.



HTTP Status Code: 306 Switch Proxy

The HTTP Status Code 306 is no longer used. The HTTP Status Code 306 originally means that subsequent requests should use the specified proxy.



HTTP Status Code: 307 Temporary Redirect (Since HTTP/1.1)

The HTTP Status Code 307 means that the request should be repeated with another URI; however, future requests should still use the original URI. In contrast to how 302 was historically implemented, the request method is not allowed to be changed when reissuing the original request. For instance, a POST request repeated using another POST request.



HTTP Status Code: 308 Permanent Redirect (Approved as Experimental RFC)

The HTTP Status Code 308 means that the request, and all future requests should be repeated using another URI. 307 and 308 (as proposed) parallel the behaviours of 302 and 301, but do not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.



HTTP Status Codes: 4xx Client Error


The HTTP Status Codes 4xx are intended for cases in which the client seems to have erred. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user.





HTTP Status Code: 400 Bad Request

The HTTP Status Code 400 means that the request cannot be fulfilled due to bad syntax.



HTTP Status Code: 401 Unauthorized

The HTTP Status Code 401 means that authentication is required and has failed or has not yet been provided, it is similar to 403 Forbidden. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. See Basic access authentication and Digest access authentication.



HTTP Status Code: 402 Payment Required

The HTTP Status Code 402 is reserved for future use. The HTTP Status Code 402 means that this code might be used as part of some form of digital cash or micropayment scheme, but that has not happened, and this code is not usually used. As an example of its use, however, Apple's MobileMe service generates a 402 error if the MobileMe account is delinquent.



HTTP Status Code: 403 Forbidden

The HTTP Status Code 403 means that the request was a valid request, but the server is refusing to respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference. On servers where authentication is required, this commonly means that the provided credentials were successfully authenticated but that the credentials still do not grant the client permission to access the resource (e.g. a recognized user attempting to access restricted content).



HTTP Status Code: 404 Not Found

The HTTP Status Code 404 means that the requested resource could not be found but may be available again in the future. Subsequent requests by the client are permissible.



HTTP Status Code: 405 Method Not Allowed

The HTTP Status Code 405 means that a request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource.



HTTP Status Code: 406 Not Acceptable

The HTTP Status Code 406 means that the requested resource is only capable of generating content not acceptable according to the Accept headers sent in the request.



HTTP Status Code: 407 Proxy Authentication Required

The HTTP Status Code 407 means that the client must first authenticate itself with the proxy.



HTTP Status Code: 408 Request Timeout

The HTTP Status Code 408 means that the server timed out waiting for the request. According to W3 HTTP specifications: "The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time."



HTTP Status Code: 409 Conflict

The HTTP Status Code 409 indicates that the request could not be processed because of conflict in the request, such as an edit conflict.



HTTP Status Code: 410 Gone

The HTTP Status Code 410 indicates that the resource requested is no longer available and will not be available again. This should be used when a resource has been intentionally removed and the resource should be purged. Upon receiving a 410 status code, the client should not request the resource again in the future. Clients such as search engines should remove the resource from their indices. Most use cases do not require clients and search engines to purge the resource, and a "404 Not Found" may be used instead.



HTTP Status Code: 411 Length Required

The HTTP Status Code 411 means that the request did not specify the length of its content, which is required by the requested resource.



HTTP Status Code: 412 Precondition Failed

The HTTP Status Code 412 means that the server does not meet one of the preconditions that the requester put on the request.



HTTP Status Code: 413 Request Entity Too Large

The HTTP Status Code 413 means that the request is larger than the server is willing or able to process.



HTTP Status Code: 414 Request-URI Too Long

The HTTP Status Code 414 means that the URI provided was too long for the server to process.



HTTP Status Code: 415 Unsupported Media Type

The HTTP Status Code 415 means that the request entity has a media type which the server or resource does not support. For example, the client uploads an image as image/svg+xml, but the server requires that images use a different format.



HTTP Status Code: 416 Requested Range Not Satisfiable

The HTTP Status Code 416 means that the client has asked for a portion of the file, but the server cannot supply that portion. For example, if the client asked for a part of the file that lies beyond the end of the file.



HTTP Status Code: 417 Expectation Failed

The HTTP Status Code 417 means that the server cannot meet the requirements of the Expect request-header field.



HTTP Status Code: 418 I'm a Teapot (RFC 2324)

The HTTP Status Code 418 was defined in 1998 as one of the traditional IETF April Fools' Jokes, in RFC 2324, Hyper Text Coffee Pot Control Protocol, and is not expected to be implemented by actual HTTP servers.



HTTP Status Code: 420 Enhance Your Calm (Twitter)

The HTTP Status Code 420 is not part of the HTTP standard, but returned by the Twitter Search and Trends API when the client is being rate limited. Other services may wish to implement the 429 Too Many Requests response code instead.



HTTP Status Code: 422 Unprocessable Entity (WebDAV; RFC 4918)

The HTTP Status Code 422 means that the request was well-formed but was unable to be followed due to semantic errors.



HTTP Status Code: 423 Locked (WebDAV; RFC 4918)

The HTTP Status Code 423 means that the resource that is being accessed is locked.



HTTP Status Code: 424 Failed Dependency (WebDAV; RFC 4918)

The HTTP Status Code 424 means that the request failed due to failure of a previous request.



HTTP Status Code: 425 Unordered Collection (Internet Draft)

The HTTP Status Code 425 was defined in drafts of "WebDAV Advanced Collections Protocol", but not present in "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol".



HTTP Status Code: 426 Upgrade Required (RFC 2817)

The HTTP Status Code 426 means that the client should switch to a different protocol such as TLS/1.0.



HTTP Status Code: 428 Precondition Required (RFC 6585)

The HTTP Status Code 428 means that the origin server requires the request to be conditional. Intended to prevent "the 'lost update' problem, where a client GETs a resource's state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict."



HTTP Status Code: 429 Too Many Requests (RFC 6585)

The HTTP Status Code 429 means that the user has sent too many requests in a given amount of time. Intended for use with rate limiting schemes.



HTTP Status Code: 431 Request Header Fields Too Large (RFC 6585)

The HTTP Status Code 431 means that the server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.



HTTP Status Code: 444 No Response (Nginx)

The HTTP Status Code 444 is used in Nginx logs to indicate that the server has returned no information to the client and closed the connection (useful as a deterrent for malware).



HTTP Status Code: 449 Retry With (Microsoft)

The HTTP Status Code 449 is a Microsoft extension, which means that the request should be retried after performing the appropriate action. Often search-engines or custom applications will ignore required parameters. Where no default action is appropriate, the Aviongoo website sends a "HTTP/1.1 449 Retry with valid parameters: param1, param2, . . ." response. The applications may choose to learn, or not.



HTTP Status Code: 450 Blocked by Windows Parental Controls (Microsoft)

The HTTP Status Code 450 is a Microsoft extension. The HTTP Status Code 450 is given when Windows Parental Controls are turned on and are blocking access to the given webpage.



HTTP Status Code: 451 Unavailable For Legal Reasons (Internet Draft)

The HTTP Status Code 451 was defined in the internet draft "A New HTTP Status Code for Legally-restricted Resources". Intended to be used when resource access is denied for legal reasons, e.g. censorship or government-mandated blocked access. A reference to the 1953 dystopian novel Fahrenheit 451, where books are outlawed.



HTTP Status Code: 494 Request Header Too Large (Nginx)

The HTTP Status Code 494 is similar to 431 but it was introduced earlier.



HTTP Status Code: 495 Cert Error (Nginx)

The HTTP Status Code 495 is used when SSL client certificate error occured to distinguish it from 4XX in a log and an error page redirection.



HTTP Status Code: 496 No Cert (Nginx)

The HTTP Status Code 496 is used when client didn't provide certificate to distinguish it from 4XX in a log and an error page redirection.



HTTP Status Code: 497 HTTP to HTTPS (Nginx)

The HTTP Status Code 497 is used for the plain HTTP requests that are sent to HTTPS port to distinguish it from 4XX in a log and an error page redirection.



HTTP Status Code: 499 Client Closed Request (Nginx)

The HTTP Status Code 499 is used in Nginx logs to indicate when the connection has been closed by client while the server is still processing its request, making server unable to send a status code back.



HTTP Status Codes: 5xx Server Error


The HTTP Status Codes 5xx mean that the server failed to fulfill an apparently valid request. The HTTP Status Codes 5xx Server Error beginning with the digit "5" indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and indicate whether it is a temporary or permanent condition. Likewise, user agents should display any included entity to the user. These response codes are applicable to any request method.





HTTP Status Code: 500 Internal Server Error

The HTTP Status Code 500 is a generic error message, given when no more specific message is suitable.



HTTP Status Code: 501 Not Implemented

The HTTP Status Code 501 means that the server either does not recognize the request method, or it lacks the ability to fulfill the request.



HTTP Status Code: 502 Bad Gateway

The HTTP Status Code 502 means that the server was acting as a gateway or proxy and received an invalid response from the upstream server.



HTTP Status Code: 503 Service Unavailable

The HTTP Status Code 503 means that the server is currently unavailable (because it is overloaded or down for maintenance). Generally, this is a temporary state.



HTTP Status Code: 504 Gateway Timeout

The HTTP Status Code 504 means that the server was acting as a gateway or proxy and did not receive a timely response from the upstream server.



HTTP Status Code: 505 HTTP Version Not Supported

The HTTP Status Code 505 means that the server does not support the HTTP protocol version used in the request.



HTTP Status Code: 506 Variant Also Negotiates (RFC 2295)

The HTTP Status Code 506 means that transparent content negotiation for the request results in a circular reference.



HTTP Status Code: 507 Insufficient Storage (WebDAV; RFC 4918)

The HTTP Status Code 507 means that the server is unable to store the representation needed to complete the request.



HTTP Status Code: 508 Loop Detected (WebDAV; RFC 5842)

The HTTP Status Code 508 means that the server detected an infinite loop while processing the request (sent in lieu of 208).



HTTP Status Code: 509 Bandwidth Limit Exceeded (Apache BW/Limited Extension)

The HTTP Status Code 509 is usesd by many servers, and is not specified in any RFCs.



HTTP Status Code: 510 Not Extended (RFC 2774)

The HTTP Status Code 510 is further extensions to the request are required for the server to fulfill it.



HTTP Status Code: 511 Network Authentication Required (RFC 6585)

The HTTP Status Code 511 means that the client needs to authenticate to gain network access. The HTTP Status Code 511 is intended for use by intercepting proxies used to control access to the network (e.g. "captive portals" used to require agreement to Terms of Service before granting full Internet access via a Wi-Fi hotspot).



HTTP Status Code: 598 Network Read Timeout Error

The HTTP Status Code 598 is not specified in any RFCs, but is used by Microsoft Corporation HTTP proxies to signal a network read timeout behind the proxy to a client in front of the proxy.



HTTP Status Code: 599 Network Connect Timeout Error

The HTTP Status Code 599 is not specified in any RFCs, but is used by Microsoft Corporation HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.



HTTP Status Codes: Further Reading



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