Http error 498

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This is a list of Hypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The optional message phrases shown are typical, but any human-readable alternative may be provided, or none at all.

Unless otherwise stated, the status code is part of the HTTP standard (RFC 9110).

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.^[1]

All HTTP response status codes are separated into five classes or categories. The first digit of the status code defines the class of response, while the last two digits do not have any classifying or categorization role. There are five classes defined by the standard:

• 1xx informational response – the request was received, continuing process
• 2xx successful – the request was successfully received, understood, and accepted
• 3xx redirection – further action needs to be taken in order to complete the request
• 4xx client error – the request contains bad syntax or cannot be fulfilled
• 5xx server error – the server failed to fulfil an apparently valid request

1xx informational response

An informational response indicates that the request was received and understood. It is issued on a provisional basis while request processing continues. It alerts the client to wait for a final response. The message consists only of the status line and optional header fields, and is terminated by an empty line. As the HTTP/1.0 standard did not define any 1xx status codes, servers must not^{[note 1]} send a 1xx response to an HTTP/1.0 compliant client except under experimental conditions.

100 Continue

The server has received the request headers and 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). Sending a large request body to a server after a request has been rejected for inappropriate headers would be inefficient. To have a server check the request’s headers, a client must send Expect: 100-continue as a header in its initial request and receive a 100 Continue status code in response before sending the body. If the client receives an error code such as 403 (Forbidden) or 405 (Method Not Allowed) then it should not send the request’s body. The response 417 Expectation Failed indicates that the request should be repeated without the Expect header as it indicates that the server does not support expectations (this is the case, for example, of HTTP/1.0 servers).^[2]

101 Switching Protocols

The requester has asked the server to switch protocols and the server has agreed to do so.

102 Processing (WebDAV; RFC 2518)

A WebDAV request may contain many sub-requests involving file operations, requiring 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.^[3] This prevents the client from timing out and assuming the request was lost.

103 Early Hints (RFC 8297)

Used to return some response headers before final HTTP message.^[4]

2xx success

This class of status codes indicates the action requested by the client was received, understood, and accepted.^[1]

200 OK

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.

201 Created

The request has been fulfilled, resulting in the creation of a new resource.^[5]

202 Accepted

The request has been accepted for processing, but the processing has not been completed. The request might or might not be eventually acted upon, and may be disallowed when processing occurs.

203 Non-Authoritative Information (since HTTP/1.1)

The server is a transforming proxy (e.g. a Web accelerator) that received a 200 OK from its origin, but is returning a modified version of the origin’s response.^[6][7]

204 No Content

The server successfully processed the request, and is not returning any content.

205 Reset Content

The server successfully processed the request, asks that the requester reset its document view, and is not returning any content.

206 Partial Content

The server is delivering only part of the resource (byte serving) due to a range header sent by the client. The range header is used by HTTP clients to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status (WebDAV; RFC 4918)

The message body that follows is by default an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.^[8]

208 Already Reported (WebDAV; RFC 5842)

The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response, and are not being included again.

226 IM Used (RFC 3229)

The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.^[9]

3xx redirection

This class of status code indicates the client must take additional action to complete the request. Many of these status codes are used in URL redirection.^[1]

A user agent may carry out the additional action with no user interaction only if the method used in the second request is GET or HEAD. A user agent may automatically redirect a request. A user agent should detect and intervene to prevent cyclical redirects.^[10]

300 Multiple Choices

Indicates multiple options for the resource from which the client may choose (via agent-driven content negotiation). For example, this code could be used to present multiple video format options, to list files with different filename extensions, or to suggest word-sense disambiguation.

301 Moved Permanently

This and all future requests should be directed to the given URI.

302 Found (Previously «Moved temporarily»)

Tells the client to look at (browse to) another URL. The HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect with the same method (the original describing phrase was «Moved Temporarily»),^[11] but popular browsers implemented 302 redirects by changing the method to GET. Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours.^[10]

303 See Other (since HTTP/1.1)

The response to the request can be found under another URI using the GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should issue a new GET request to the given URI.

304 Not Modified

Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match. In such case, there is no need to retransmit the resource since the client still has a previously-downloaded copy.

305 Use Proxy (since HTTP/1.1)

The requested resource is available only through a proxy, the address for which is provided in the response. For security reasons, many HTTP clients (such as Mozilla Firefox and Internet Explorer) do not obey this status code.

306 Switch Proxy

No longer used. Originally meant «Subsequent requests should use the specified proxy.»

307 Temporary Redirect (since HTTP/1.1)

In this case, 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 example, a POST request should be repeated using another POST request.

308 Permanent Redirect

This and all future requests should be directed to the given URI. 308 parallel the behaviour of 301, but does not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.

4xx client errors

This class of status code is intended for situations in which the error seems to have been caused by the client. 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.

400 Bad Request

The server cannot or will not process the request due to an apparent client error (e.g., malformed request syntax, size too large, invalid request message framing, or deceptive request routing).

401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. 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. 401 semantically means «unauthorised», the user does not have valid authentication credentials for the target resource.

Some sites incorrectly issue HTTP 401 when an IP address is banned from the website (usually the website domain) and that specific address is refused permission to access a website.^{[citation needed]}

402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, as proposed, for example, by GNU Taler,^[13] but that has not yet happened, and this code is not widely used. Google Developers API uses this status if a particular developer has exceeded the daily limit on requests.^[14] Sipgate uses this code if an account does not have sufficient funds to start a call.^[15] Shopify uses this code when the store has not paid their fees and is temporarily disabled.^[16] Stripe uses this code for failed payments where parameters were correct, for example blocked fraudulent payments.^[17]

403 Forbidden

The request contained valid data and was understood by the server, but the server is refusing action. This may be due to the user not having the necessary permissions for a resource or needing an account of some sort, or attempting a prohibited action (e.g. creating a duplicate record where only one is allowed). This code is also typically used if the request provided authentication by answering the WWW-Authenticate header field challenge, but the server did not accept that authentication. The request should not be repeated.

404 Not Found

The requested resource could not be found but may be available in the future. Subsequent requests by the client are permissible.

405 Method Not Allowed

A request method is not supported for the requested resource; for example, a GET request on a form that requires data to be presented via POST, or a PUT request on a read-only resource.

406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request. See Content negotiation.

407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

408 Request Timeout

The server timed out waiting for the request. According to 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.»

409 Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource, such as an edit conflict between multiple simultaneous updates.

410 Gone

Indicates that the resource requested was previously in use but 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 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.

411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request header fields.

413 Payload Too Large

The request is larger than the server is willing or able to process. Previously called «Request Entity Too Large» in RFC 2616.^[18]

414 URI Too Long

The URI provided was too long for the server to process. Often the result of too much data being encoded as a query-string of a GET request, in which case it should be converted to a POST request. Called «Request-URI Too Long» previously in RFC 2616.^[19]

415 Unsupported Media Type

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.

416 Range Not Satisfiable

The client has asked for a portion of the file (byte serving), 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. Called «Requested Range Not Satisfiable» previously RFC 2616.^[20]

417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.^[21]

418 I’m a teapot (RFC 2324, RFC 7168)

This code 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. The RFC specifies this code should be returned by teapots requested to brew coffee.^[22] This HTTP status is used as an Easter egg in some websites, such as Google.com’s «I’m a teapot» easter egg.^[23][24][25] Sometimes, this status code is also used as a response to a blocked request, instead of the more appropriate 403 Forbidden.^[26][27]

421 Misdirected Request

The request was directed at a server that is not able to produce a response (for example because of connection reuse).

422 Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.^[8]

423 Locked (WebDAV; RFC 4918)

The resource that is being accessed is locked.^[8]

424 Failed Dependency (WebDAV; RFC 4918)

The request failed because it depended on another request and that request failed (e.g., a PROPPATCH).^[8]

425 Too Early (RFC 8470)

Indicates that the server is unwilling to risk processing a request that might be replayed.

426 Upgrade Required

The client should switch to a different protocol such as TLS/1.3, given in the Upgrade header field.

428 Precondition Required (RFC 6585)

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.^[28]

429 Too Many Requests (RFC 6585)

The user has sent too many requests in a given amount of time. Intended for use with rate-limiting schemes.^[28]

431 Request Header Fields Too Large (RFC 6585)

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.^[28]

451 Unavailable For Legal Reasons (RFC 7725)

A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.^[29] The code 451 was chosen as a reference to the novel Fahrenheit 451 (see the Acknowledgements in the RFC).

5xx server errors

The server failed to fulfil a request.

Response status codes 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.

500 Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

501 Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request. Usually this implies future availability (e.g., a new feature of a web-service API).

502 Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503 Service Unavailable

The server cannot handle the request (because it is overloaded or down for maintenance). Generally, this is a temporary state.^[30]

504 Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

505 HTTP Version Not Supported

The server does not support the HTTP version used in the request.

506 Variant Also Negotiates (RFC 2295)

Transparent content negotiation for the request results in a circular reference.^[31]

507 Insufficient Storage (WebDAV; RFC 4918)

The server is unable to store the representation needed to complete the request.^[8]

508 Loop Detected (WebDAV; RFC 5842)

The server detected an infinite loop while processing the request (sent instead of 208 Already Reported).

510 Not Extended (RFC 2774)

Further extensions to the request are required for the server to fulfill it.^[32]

511 Network Authentication Required (RFC 6585)

The client needs to authenticate to gain network access. 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).^[28]

Unofficial codes

The following codes are not specified by any standard.

419 Page Expired (Laravel Framework)

Used by the Laravel Framework when a CSRF Token is missing or expired.

420 Method Failure (Spring Framework)

A deprecated response used by the Spring Framework when a method has failed.^[33]

420 Enhance Your Calm (Twitter)

Returned by version 1 of the Twitter Search and Trends API when the client is being rate limited; versions 1.1 and later use the 429 Too Many Requests response code instead.^[34] The phrase «Enhance your calm» comes from the 1993 movie Demolition Man, and its association with this number is likely a reference to cannabis.^{[citation needed]}

430 Request Header Fields Too Large (Shopify)

Used by Shopify, instead of the 429 Too Many Requests response code, when too many URLs are requested within a certain time frame.^[35]

450 Blocked by Windows Parental Controls (Microsoft)

The Microsoft extension code indicated when Windows Parental Controls are turned on and are blocking access to the requested webpage.^[36]

498 Invalid Token (Esri)

Returned by ArcGIS for Server. Code 498 indicates an expired or otherwise invalid token.^[37]

499 Token Required (Esri)

Returned by ArcGIS for Server. Code 499 indicates that a token is required but was not submitted.^[37]

509 Bandwidth Limit Exceeded (Apache Web Server/cPanel)

The server has exceeded the bandwidth specified by the server administrator; this is often used by shared hosting providers to limit the bandwidth of customers.^[38]

529 Site is overloaded

Used by Qualys in the SSLLabs server testing API to signal that the site can’t process the request.^[39]

530 Site is frozen

Used by the Pantheon Systems web platform to indicate a site that has been frozen due to inactivity.^[40]

598 (Informal convention) Network read timeout error

Used by some HTTP proxies to signal a network read timeout behind the proxy to a client in front of the proxy.^[41]

599 Network Connect Timeout Error

An error used by some HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.

Internet Information Services

Microsoft’s Internet Information Services (IIS) web server expands the 4xx error space to signal errors with the client’s request.

440 Login Time-out

The client’s session has expired and must log in again.^[42]

449 Retry With

The server cannot honour the request because the user has not provided the required information.^[43]

451 Redirect

Used in Exchange ActiveSync when either a more efficient server is available or the server cannot access the users’ mailbox.^[44] The client is expected to re-run the HTTP AutoDiscover operation to find a more appropriate server.^[45]

IIS sometimes uses additional decimal sub-codes for more specific information,^[46] however these sub-codes only appear in the response payload and in documentation, not in the place of an actual HTTP status code.

nginx

The nginx web server software expands the 4xx error space to signal issues with the client’s request.^[47][48]

444 No Response

Used internally^[49] to instruct the server to return no information to the client and close the connection immediately.

494 Request header too large

Client sent too large request or too long header line.

495 SSL Certificate Error

An expansion of the 400 Bad Request response code, used when the client has provided an invalid client certificate.

496 SSL Certificate Required

An expansion of the 400 Bad Request response code, used when a client certificate is required but not provided.

497 HTTP Request Sent to HTTPS Port

An expansion of the 400 Bad Request response code, used when the client has made a HTTP request to a port listening for HTTPS requests.

499 Client Closed Request

Used when the client has closed the request before the server could send a response.

Cloudflare

Cloudflare’s reverse proxy service expands the 5xx series of errors space to signal issues with the origin server.^[50]

520 Web Server Returned an Unknown Error

The origin server returned an empty, unknown, or unexpected response to Cloudflare.^[51]

521 Web Server Is Down

The origin server refused connections from Cloudflare. Security solutions at the origin may be blocking legitimate connections from certain Cloudflare IP addresses.

522 Connection Timed Out

Cloudflare timed out contacting the origin server.

523 Origin Is Unreachable

Cloudflare could not reach the origin server; for example, if the DNS records for the origin server are incorrect or missing.

524 A Timeout Occurred

Cloudflare was able to complete a TCP connection to the origin server, but did not receive a timely HTTP response.

525 SSL Handshake Failed

Cloudflare could not negotiate a SSL/TLS handshake with the origin server.

526 Invalid SSL Certificate

Cloudflare could not validate the SSL certificate on the origin web server. Also used by Cloud Foundry’s gorouter.

527 Railgun Error

Error 527 indicates an interrupted connection between Cloudflare and the origin server’s Railgun server.^[52]

530

Error 530 is returned along with a 1xxx error.^[53]

AWS Elastic Load Balancer

Amazon’s Elastic Load Balancing adds a few custom return codes

460

Client closed the connection with the load balancer before the idle timeout period elapsed. Typically when client timeout is sooner than the Elastic Load Balancer’s timeout.^[54]

463

The load balancer received an X-Forwarded-For request header with more than 30 IP addresses.^[54]

561 Unauthorized

An error around authentication returned by a server registered with a load balancer. You configured a listener rule to authenticate users, but the identity provider (IdP) returned an error code when authenticating the user.^[55]

Caching warning codes (obsoleted)

The following caching related warning codes were specified under RFC 7234. Unlike the other status codes above, these were not sent as the response status in the HTTP protocol, but as part of the «Warning» HTTP header.^[56][57]

Since this «Warning» header is often neither sent by servers nor acknowledged by clients, this header and its codes were obsoleted by the HTTP Working Group in 2022 with RFC 9111.^[58]

110 Response is Stale

The response provided by a cache is stale (the content’s age exceeds a maximum age set by a Cache-Control header or heuristically chosen lifetime).

111 Revalidation Failed

The cache was unable to validate the response, due to an inability to reach the origin server.

112 Disconnected Operation

The cache is intentionally disconnected from the rest of the network.

113 Heuristic Expiration

The cache heuristically chose a freshness lifetime greater than 24 hours and the response’s age is greater than 24 hours.

199 Miscellaneous Warning

Arbitrary, non-specific warning. The warning text may be logged or presented to the user.

214 Transformation Applied

Added by a proxy if it applies any transformation to the representation, such as changing the content encoding, media type or the like.

299 Miscellaneous Persistent Warning

Same as 199, but indicating a persistent warning.

See also

• Custom error pages
• List of FTP server return codes
• List of HTTP header fields
• List of SMTP server return codes
• Common Log Format

Explanatory notes

References

External links

• «RFC 9110: HTTP Semantics and Content, Section 15 «Status Codes»«.
• Hypertext Transfer Protocol (HTTP) Status Code Registry

Last Edited January 25, 2018 by
Garenne Bigby in Blog

HTTP or Hypertext Transfer Protocol response status codes include status codes from internet standards, other IETF RFCs, IETF, and others. The first digit of the status code indicates one of the five classes of response. These classes must be recognized by an HTTP client. The Internet Assigned Numbers Authority (IANA) governs the official registry of HTTP status codes. Additional decimal sub-codes provide a little more specific information and direction. The following list details what each of the five classes mean as well as the specific decimal sub-codes under each class.

 
1xx

Codes under the 1xx coding specify a provisional response. These responses are comprised of optional headers and the status-line and is completed by an empty line. No required headers are needed for this class of status code. Servers are not allowed to send a 1xx response to an HTTP/1.0 client unless certain conditions exist. This is because HTTP/1.0 did not define any 1xx status codes. Keep in mind that a client must be prepared to accept one or more 1xx status responses before a regular response. This is even if the client does not expect a 100 (Continue) status message. However, unexpected 1xx status responses can be ignored by a user agent.

100 Continue

This code describes an incident where the server has received the request headers and the client can go ahead and now send the request. Sending a larger request body to a server after a request has already been rejected due to inappropriate headers is not proper. A client wanting to have a server verify the request’s headers needs to send “Expect: 100-continue” as a header in its first request and receive a 100 Continue status code in response before sending the body. A response of “417 Expectation Failed” is an indication that the request should be discontinued.

101 Switching Protocols

This status response indicates that the entity making the request has asked the server to change protocols and the server has acquiesce to the request.

102 Processing (WebDAV; RFC 2518)

This code indicates that a server has received a WebDAV request and is processing it. A WebDAV request can contain many sub-requests within it and can also require a long time to fulfill the application. This code can prevent the client from timing out presuming that the request was missing.

2xx

The class of codes under 2xx indicate that the server has received client’s request, understands said request, accepts it and has processed it successfully.

200 OK

A response of 200 OK is a standard response for any successful HTTP request. It depends on the type of request in terms of what response is issued. When it comes to a “GET request,” the response will have a unit that corresponds to the request. In a “POST” request, the response contains an entity describing the end result.

201 Created

This code indicates that a request has been fulfilled and has resulted in the creation of a new resource.

202 Accepted

A 202 Accepted code means that the request has been confirmed and accepted for processing; however, the procedure has not been completed. While it is processing, the request may or may not ultimately be acted upon or it may be forbidden when the processing occurs.

203 Non-Authoritative Information (since HTTP/1.1)

This response indicates that the server, as a transforming proxy or Web accelerator, has received a 200 OK from its origin but is returning a modified version of the origin’s response.

204 No Content

A 204 No Content status response means that the server has successfully received and processed the request and is not returning any substance.

205 Reset Content

This status response means that the server has processed the request but is not responding with content. However, even though a 204 response means a similar result, a 205 Reset Content response requires the requester reset the document view to continue.

206 Partial Content (RFC 7233)

A 206 Partial Content code tells that the server is returning only a partial answer, such as a byte serving, due to a range header requested. This range header is applied by clients to authorize resuming of intermittent downloads or split a download into various simultaneous streams.

207 Multi-Status (WebDAV; RFC 4918)

A 207 message indicates that the response that follows is an XML message. This message can include a number of discrete response codes. These responses can depend on the amount of sub-requests that were initiated by the client.

208 Already Reported (WebDAV; RFC 5842)

A 208 code indicates that those of a DAV agreement have formerly been counted and listed in an earlier reply to the request and aren’t being incorporated any more.

226 IM Used (RFC 3229)

A 226 IM Used response means that the server has fulfilled a request for the resource; however, the response is a demonstration of the result of at least one or more instance-manipulations assigned to the current instance.

3xx Redirection

Statuses under 3xx are codes that indicate that the client is required to take additional steps to complete a request. Many 3xx status codes are used in URL redirection. A user agent may carry out this additional action with absolutely no user interaction. However, this can only happen if the method used in this second request is GET or HEAD. In the alternative, a user agent may also automatically redirect a request. It is important, though, that the user agent detects and intervenes in order to prevent cyclical redirects.

300 Multiple Choices

A 300-multiple choice response indicates that multiple options for the resource from which the client may choose exist. These options can include agent-driven content negotiation. One example of this could be used to prevent multiple video format options by listing the files with different filename extensions.

301 Moved Permanently

A response of 301 Moved Permanently means that this and all future requests should be directed to the selected URL.

302 Found

A 302 response indicates that a HTTP/1.0 specification (RFC 1945) requires the client to perform a temporary redirect. This response is an example of industry practices contradicting the standard. Originally this response was described as “moved temporarily.” However, browsers implemented 302 as a response, and with the functionality of a 303. As a result, HTTP/1.1 added status codes 307 and 303 to differentiate between the two. Some Web applications continue to use the 302 status code, though, as if it were 303.

303 See Other (since HTTP/1.1)

A 303 response can be found using a GET method under another URI. When this is obtained in response to a PUT/DELETE or POST, the client should assume that the server has received the data and should expect a redirect with a separate GET message.

304 Not Modified (RFC 7232)

A 304 Not Modified response signifies that the resource has not been modified since the version indicated by the request headers “If-None-Match” or “If-Modified-Since” responses were given. In this situation, no need exists to retransmit the resource since the client still has a downloaded copy.

305 Use Proxy (since HTTP/1.1)

A 305 response means that the requested resource is only available through a proxy. The proxy is the address provided in the response. Mozilla and Internet Explorer are two HTTP clients who do not handle responses with this status code, for security reasons.

306 Switch Proxy

This status response is no longer in use. It initially indicated that subsequent requests should return to the specified proxy.

307 Temporary Redirect (since HTTP/1.1)

A request receiving a 307 response should be repeated with another URI. Future requests, though, should still use the original URI. In the past, requests resulting in a 302 response were not permitted to be changed when reissuing the primary request. One example of this is a POST request that should be repeated using a different POST request.

308 Permanent Redirect (RFC 7538)

A 308 response indicates that the current request and all forthcoming requests should be repeated using another URI. Responses under 307 and 308 parallel the actions of 301 and 302 responses. However these do not allow the HTTP method to change.

4xx Client Error

The 4xx class of status codes are meant for situations where the client has erred. The server should contain an entity encompassing some type of explanation of the error condition including both temporary and permanent conditions. These error codes are applicable to any request methods, and user agents should display them to any included entity to the user.

400 Bad Request

A 400 request means that the server can or will not process the request because of a client error. This error can be a malformed request syntax, deceptive request routing, invalid request message framing, or size that is too large.

401 Unauthorized (RFC 7235)

A 401 response is used for when authentication is required and has failed or has yet to be provided. This response should include a WWW-Authenticate header field which contains a challenge that is applicable to the entreated resource, such as a digit access authentication and basic access authentication. 401 means “unauthenticated,” meaning the user does not have the needed credentials. Some sites give a 401 when an IP address is otherwise banned from the website and that particular address is denied permission to access a certain site.

402 Payment Required

A 402 response is reserved for future use. This code was originally intended to be used as a form of digital cash or micropayment. However, currently this code is not used. Google Developers API use this status, however, if a particular developer has gone over the daily limit on requests.

403 Forbidden

A 403 Forbidden response means that the request was valid, but the server is declining to react to it. This can be for several reasons, one of them being the user might be logged in but not have the required permissions to access the resource.

404 Not Found

This response means that the bidden resource cannot be found but could be available in the future. It also means that subsequent requests by the client are allowed.

405 Method Not Allowed

A 405 Method Not Allowed means that a request method used was not supported for the requested resource. For example, a GET request on a form may require a PUT request on a read-only resource or data that needs to be presented via POST.

406 Not Acceptable

A 406 response means that the bidden resource is only capable of producing content that is not acceptable set by the Accept headers attached in the application.

407 Proxy Authentication Required (RFC 7235)

A 407 proxy authentication required response means that the client should first validate itself with the proxy.

408 Request Time-out

This type of response means that the server has timed out while waiting for the request. In accordance with the 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.»[a]

409 Conflict

A 409 Conflict response means that due to a conflict in the request, it could not have be processed. This can include an edit conflict between various concurrent updates.

410 Gone

A 410 Gone response means that the resource that is being requested is no longer available nor will it be available again. A 410 Gone response should be received when the resource was intentionally removed or when the resource should be purged. The client should not request this resource in the future and search engines should eliminate the resource from their indices. However, most use cases do not require this absolute of a response and do not require search engines and clients to purge the resources, allowing a 404 Not Found response to be used instead.

411 Length Required

A 411 Length Required response indicates that the request did not state the length of content, which is needed by the requested resource.

412 Precondition Failed (RFC 7232)

This response indicates that the server does not meet one of the preconditions that is required of that request.

413 Payload Too Large (RFC 7231)

When a request is more than the server is capable of processing, a 413 Payload Too Large response will be given. This was originally called a “Request Entity Too Large” response.

414 URI Too Long (RFC 7231)

If a URI given was too long for the server to process, a 414 URI Too Long response is given. This response can often be the result of large amounts data being encoded as a query-string of a GET request. In this event, it should be converted to a POST request.

415 Unsupported Media Type

A 415 Unsupported Media Type means that the request entity has a media type which the server or resource does not support. If a client uploads an image in one format, but the server requires another format, a 415 Unsupported Media Type response may be given.

416 Range Not Satisfiable (RFC 7233)

A 416 Range Not Satisfiable response code indicates that the client has asked for a portion of the file, such as a byte serving, but the server cannot satisfy that request for that portion. Perhaps the request is for a part of the file that is beyond the end of the file. That request would result in a 416 response.

417 Expectation Failed

A 417 Expectation Failed response code will come when the server cannot meet the demands of the “Expect” request-header field.

418 I’m a teapot (RFC 2324)

The title of this code response seems a little tongue in cheek, and perhaps that could be because the code was defined in 1998 as one of the IETF April Fool’s Jokes in reference to RFC 2324 Hyper Text Coffee Pot Control Protocol. It was not expected to be employed by actual HTTP servers. The RFC states this code should be in response by teapots entreated to brew coffee. It is often used as an “Easter egg” in some sites, including Google.

421 Misdirected Request (RFC 7540)

A 421 Misdirected Request response means that the request given was directed at a server that is simply not able to produce a response.

422 Unprocessable Entity (WebDAV; RFC 4918)

A 422 Unprocessable Entity response is when a request was well-formed, but the server could not follow the request due to semantic errors within the request.

423 Locked (WebDAV; RFC 4918)

A 423 Locked response occurs when the resource being sort is locked.

424 Failed Dependency (WebDAV; RFC 4918)

This response occurs when the request being made fails due to the failure of an earlier request.

426 Upgrade Required

A 426 Upgrade Required response is a result of a client needing to switch to a different protocol before a request can be completed. This switch could be to a TLS/1.0 provided in the Upgrade header field.

428 Precondition Required (RFC 6585)

This response is the request of a request being made through the origin server that requires the request to be conditional. This response is intended to stop the “lost update” problem often given when a client GETs a resource’s state, and PUTs it to the server after changing it while, at the same time, another party has modified the state on the server, resulting in a conflict between the two.

429 Too Many Requests (RFC 6585)

When a user has sent an excessive amount of requests in a specified timeframe, they will receive a 429 “To Many Requests” response. This response is intended for use with rate-limiting schemes.

431 Request Header Fields Too Large (RFC 6585)

A server that is reluctant to process a request because all of the header fields collectively or the individual header field are too large will result in this 431 response.

451 Unavailable For Legal Reasons

When a server operator has gotten a legal request to a set of resources that include the requested resource or to deny access to a resource, a code 451 response will be given. The specific number 451 is in reference to the novel Fahrenheit 451.

5xx Server Error

The 5xx class of codes are responses to requests that servers fail to fulfill. These response status codes indicate cases where the server is sent a response, it is aware it is incapable of performing the request or has encountered an error. These response codes are applicable in any type of request method. The server should include some type of entity containing an explanation of what the error situation involves and indicate whether this error is a temporary or permanent one. User agents should also display any included entity to the user.

500 Internal Server Error

A 500 Internal Server Error response is essentially a generic error message. You see these messages when an unexpected condition is encountered and no other 500 message is applicable.

501 Not Implemented

A 501 response occurs when the server does not have the ability to fulfill the request or the server does not recognize the method through which the request is sent. This type of response does imply that it could be available in the future.

502 Bad Gateway

A 502 Bad Gateway response is given in situations where a server was acting as a proxy or gateway and received an invalid reply from the upstream server.

503 Service Unavailable

In this type of response, the server is unavailable due to it being overloaded or down for maintenance. A 503 Service Unavailable response is a temporary error response.

504 Gateway Time-out

A 504 Gateway Time-out response comes when a server was acting as a gateway or proxy and it did not receive a timely response from the upstream server, thereby “timing out” the request.

505 HTTP Version Not Supported

This response comes when a server does not support the HTTP protocol version used in a demand.

506 Variant Also Negotiates (RFC 2295)

A 506 response comes when transparent content negotiation for a specific request results in circular references.

507 Insufficient Storage (WebDAV; RFC 4918)

When a server is incapable of storing the representation that is needed to complete a request, a 507 Insufficient Storage response results.

508 Loop Detected (WebDAV; RFC 5842)

In these situations, a 508 Loop Detected response indicates that the server has detected an immeasurable loop while handling the request. This response is sent in lieu of a 208 Already Reported response.

510 Not Extended (RFC 2774)

A 510 error response occurs when further extensions to the request are needed in order for the server to fully fulfill the request.

511 Network Authentication Required (RFC 6585)

In 511 error response, the client needs to authenticate in order to gain network access. This type of error was created as a means to intercept proxies used to control access to the network. One example of this is “captive portals” that is used to require agreement to the Terms of Service before allowing full Internet access by means of a Wi-Fi hotspot connection.

Unofficial codes

Not all codes are specified by a specific RFC but are still utilized by third-party services to provide RESTful or semantic error responses. Below are the most commonly-used “unofficial codes” utilized.

103 Checkpoint

A 103 Checkpoint response is used in the resumable requests application to resume aborted POST or PUT requests.

420 Method Failure (Spring Framework)

A 420 Method Failure response comes from the Spring Framework when a process has failed.

419 I’m a Fox (Smoothwall/Foxwall)

This response is returned through versions of Foxwall or Smoothwall firewall systems in response to when a configuration test is returned.

420 Enhance Your Calm (Twitter)

Twitter Version 1 issued a 420 Enhance Your Calm error response when the client was being rate-limited. However, Versions 1.1 and later versions used the 429 Too Many Requests response code as an alternative.

450 Blocked by Windows Parental Controls (Microsoft)

The 450 Block by Windows Parental Control response is a Microsoft-specific extension. It is an error given when the Windows Parental Controls are activated and are responding by blocking access to a certain site that does not qualify through the parameters set through the controls.

498 Invalid Token (Esri)

A 498 Invalid Token response is returned by ArcGIS for Server. This code indicates an invalid or expired token.

499 Token Required (Esri)

Another error returned by ArcGIS for Server, 499 indicates that token is required and still needs to be submitted to proceed.

499 Antivirus has Forbidden a Request

A 499 error is produced when a malicious site is intercepted and the request cannot go through.

509 Bandwidth Limit is Exceeded (Apache Web Server/cPanel)

In situations where a server has gone over the bandwidth quantified by a server administrator, users will receive a 509 Bandwidth Limit Exceeded error. This response is used by shared hosting providers to keep a limit on customer bandwidth.

530 Site is frozen

A 530 Site is frozen is an error employed by Pantheon in order to point out that a website has been frozen because of inactivity.

440 Login Timeout

When a client’s session has expired, a 440 Login Timeout response will appear, instructing the user to log in again to proceed with his request.

449 Retry With

A 449 error appears when the server cannot honor a request because the user has not given all of the needed information in order to fulfill a request.

451 Redirect

A 451 Redirect error is used in Exchange ActiveSync when the server cannot access the user’s mailbox or a more efficient server is available to complete a request. The error instructs the client to re-run the HTTP AutoDiscover operation to find a more valid server to proceed.

Nginx

The nginx web server software expands the 4xx error response space in an effort to signal issues with the client’s specific request. These errors are used solely for logging purpose, and no definite response is sent with these codes.

444 No Response

A 444 No Response error indicates that the server has closed the connection with no returned information from a client request.

495 SSL Certificate Error

A 495 SSL Certificate Error is an expansion of the 400 Bad Request error response code and is used when the client has given an invalid client certificate when making a request.

496 SSL Certificate Required

A 496 SSL Certificate Required error response is an additional expansion of the 400 Bad Request response code. This response is used when a client certificate is required to complete a request but is not provided.

497 HTTP Request Sent to HTTPS Port

Again, another expansion of the 400 Bad Request error response code, a 497 HTTP Request Sent to HTTPS Port is used when a client has made an HTTP request to a port that is listening for HTTPS requests specifically.

499 Client Closed Request

A 499 Client Closed Request is used when the client has closed the request before the server could complete the task and send a response.

Cloudflare

Cloudflare’s reverse proxy service is an expansion of the 5xx error space used to specify issues with the origin server.

520 Unknown Error

A 520 Unknown Error code is used as a “catch-all response” in the event that the origin server yields something unexpected. This could include listing large headers, connection resets or invalid or empty responses.

521 Web Server Is Down

When the origin server has rejected the connection from Cloudflare, a 521 Web Server is Down error response will be given.

522 Connection Timed Out

A 522 Connection Timed Out response is issued when Cloudflare could not assign a TCP handshake with the server of origin.

523 Origin Is Unreachable

When Cloudflare cannot reach the origin server, a 523 Origin is Unreachable error response is given. For example, if the DNS files for the origin server are incorrect, a 523 error will be given.

524 A Timeout Occurred

If Cloudflare is able to justify a TCP connection to the origin server but did not obtain a timely HTTP response, users will see a 524 A Timeout Occurred error response.

525 SSL Handshake Failed

A 525 SSL Handshake Failed error occurs when Cloudflare could not transfer a TLS/ SSL handshake with the server of origin.

526 Invalid SSL Certificate

When Cloudflare cannot authenticate the SSL/TLS certificate that has been presented by the origin server, a 526 error will result.

527 Railgun Error

When requests time out or fail after the WAN connection has been recognized, a 527 Railgun Error response will result.

[a]From this link: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Back

2015-11-13 21:23:35 xxx.xxx.252.55 GET /arcgis/rest/services/20151111_160549/MapServer f=json&dpi=96&transparent=true&format=png24&callback=dojo.io.script.jsonp_dojoIoScript1._jsonpCallback&token=VJ28RfEexve3xevsgw3gsw43gsxdgsszewMtlgybEmV_snK_Qw-uhgV2TXQKtjYqYIOnIHwfevDGHsdcejdz3zjIpSQg18AdT_qo4pzbmYsegaehRY6omQ1ChEQaZXZKJ2yBuUnzGzfMx4JdSDfasewrhSEgsfJzQYmfBeUmuKTHR4Q.. 443 - xxx.xxx.26.103 - 200 0 0 148
2015-11-13 21:23:35 xxx.xxx.252.55 POST /portal/sharing/rest/oauth2/token - 443 - xxx.xxx.26.103 - 200 0 0 335
2015-11-13 21:23:35 xxx.xxx.252.55 GET /portal/sharing/rest/generateToken token=wMAAEBUthG1-qcfW2WobFWPOyUGknoobhsgeagsaefasceoJUdQEkGIRiRrP2LMcx3R00RPEsh_hXRCS103zPxn-XJPA_wXcNMaserF40vDmUfp2uEGhnYawhbeahaeESseghsef4ZjyPdCBMnDmbkp-qgRkde2dgSEferggaA..&serverURL=https://servername.com&f=json 443 - xxx.xxx.26.103 - 200 0 0 76
2015-11-13 21:23:35 xxx.xxx.252.55 GET /arcgis/rest/services/20151111_160549/MapServer f=json&dpi=96&transparent=true&format=png24&callback=dojo.io.script.jsonp_dojoIoScript1._jsonpCallback&token=VJ28RfEK92YIqPe51T165BMtlgybEmV_snK_Qw-uhgV2TXQKtjYqYIOnIHQ1SdAtsaeh43s153zjIpSQg18AdT_qo4pzbmYCl4XRY6omQ1ChEQaZXZKJ2yBuUnzGzfMx4Jd0UXHv2JzQYmfBeUmuKTHR4Q..&token=oxc5gCxtyo-BbsQRNJ_dJZPY2mqSh320R9_NyQUesheN9ufhDBpc_4RPWUXZlrc02XwXEIwAFTLgw-lOaU9aMisrgVq3ygsdhsefsaU00a0oCMKGkV6DEqWP823Mow-EeHqhd8A3gas34xdvHDWmdzV2PwUAfQ.. 443 - xxx.xxx.26.103 - 200 0 0 323

2015-11-13 21:28:02 W3SVC2 ProxyServerName xxx.xxx.26.103 GET /headout/proxy/proxy.ashx https://servername.com/arcgis/rest/services/20151111_160549/MapServer?f=json&dpi=96&transparent=true&format=png24&callback=dojo.io.script.jsonp_dojoIoScript1._jsonpCallback 443 - xxx.xxx.37.6 HTTP/1.1 Mozilla/5.0+(Windows+NT+6.1;+WOW64;+rv:42.0)+Gecko/20100101+Firefox/42.0 _ga=GA1.2.351467188.1433864146;+__utma=1946916748.351467188.1435164146.1446129528.1446129528.1;+__utmz=194696306.1446346528.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none);+__utma=88450255.351467188.1433864146.1446061716.1446660452.6;+__utmz=88450255.1441288741.3.2.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=(not%20provided) - ProxyServerName.com 200 0 0 661 871 904

<Msg time="2015-11-13T15:08:07,261" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">In RServlet</Msg>
<Msg time="2015-11-13T15:08:07,374" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Request host: servername.com</Msg>
<Msg time="2015-11-13T15:08:07,374" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Request address: 2032:9229:f233:0:0:0:9531:f652</Msg>
<Msg time="2015-11-13T15:08:07,379" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">In AdminSecurityPreHandler</Msg>
<Msg time="2015-11-13T15:08:07,378" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Referer: http://localhost/proxy/proxy.ashx</Msg>
<Msg time="2015-11-13T15:08:07,379" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Time (ms): 118 (/arcgis/rest/services/20151111_160549/MapServer)</Msg>
<Msg time="2015-11-13T15:08:07,378" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Exception caught while validating token. Could not decrypt token. Token may not be valid.</Msg>
<Msg time="2015-11-13T15:08:07,780" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">In RServlet</Msg>
<Msg time="2015-11-13T15:08:07,878" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Request host: servername.com</Msg>
<Msg time="2015-11-13T15:08:07,878" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Request address: 2032:9229:f233:0:0:0:9531:f652</Msg>
<Msg time="2015-11-13T15:08:07,882" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Referer: http://localhost/proxy/proxy.ashx</Msg>
<Msg time="2015-11-13T15:08:07,883" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">In AdminSecurityPreHandler</Msg>
<Msg time="2015-11-13T15:08:07,883" type="DEBUG" code="9999" source="Server" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Exception caught while validating token. Could not decrypt token. Token may not be valid.</Msg>
<Msg time="2015-11-13T15:08:07,883" type="DEBUG" code="9999" source="Rest" process="2728" thread="20" methodName="" machine="SERVERNAME.COM" user="" elapsed="">Time (ms): 103 (/arcgis/rest/services/20151111_160549/MapServer)</Msg>

Информационные 100 Continue «Продолжить». Этот промежуточный ответ указывает, что запрос успешно
принят и клиент может продолжать присылать запросы либо проигнорировать
этот ответ, если запрос был завершён. Только HTTP/1.1 101 Switching Protocol «Переключение протокола». Этот код присылается в ответ на запрос
клиента, содержащий заголовок Upgrade:, и указывает, что
сервер переключился на протокол, который был указан в заголовке. Эта
возможность позволяет перейти на несовместимую версию протокола и обычно
не используется. Только HTTP/1.1 102 Processing «В обработке». Этот код указывает, что сервер получил запрос и
обрабатывает его, но обработка ещё не завершена. Только HTTP/1.1 103 Early Hints «Ранние подсказки». В ответе сообщаются ресурсы, которые могут быть
загружены заранее, пока сервер будет подготавливать основной ответ.
RFC 8297 (Experimental). Только HTTP/1.1 Успешные 200

OK

«Успешно». Запрос успешно обработан. Что значит «успешно», зависит от
метода HTTP, который был запрошен:

• GET: «ПОЛУЧИТЬ». Запрошенный ресурс был найден и передан в теле
  ответа.
• HEAD: «ЗАГОЛОВОК». Заголовки переданы в ответе.
• POST: «ПОСЫЛКА». Ресурс, описывающий результат действия сервера на
  запрос, передан в теле ответа.
• TRACE: «ОТСЛЕЖИВАТЬ». Тело ответа содержит тело запроса полученного
  сервером.

HTTP/0.9 и выше 201 Created «Создано». Запрос успешно выполнен и в результате был создан ресурс.
Этот код обычно присылается в ответ на запрос PUT «ПОМЕСТИТЬ». HTTP/0.9 и выше 202 Accepted «Принято». Запрос принят, но ещё не обработан. Не поддерживаемо, т.е.,
нет способа с помощью HTTP отправить асинхронный ответ позже, который
будет показывать итог обработки запроса. Это предназначено для случаев,
когда запрос обрабатывается другим процессом или сервером, либо для
пакетной обработки. HTTP/0.9 и выше 203 Non-Authoritative Information «Информация не авторитетна». Этот код ответа означает, что информация,
которая возвращена, была предоставлена не от исходного сервера, а из
какого-нибудь другого источника. Во всех остальных ситуациях более
предпочтителен код ответа 200 OK. HTTP/0.9 и 1.1 204 No Content «Нет содержимого». Нет содержимого для ответа на запрос, но заголовки
ответа, которые могут быть полезны, присылаются. Клиент может
использовать их для обновления кешированных заголовков полученных ранее
для этого ресурса. HTTP/0.9 и выше 205 Reset Content «Сбросить содержимое». Этот код присылается, когда запрос обработан,
чтобы сообщить клиенту, что необходимо сбросить отображение документа,
который прислал этот запрос. Только HTTP/1.1 206 Partial Content «Частичное содержимое». Этот код ответа используется, когда клиент
присылает заголовок диапазона, чтобы выполнить загрузку отдельно, в
несколько потоков. Только HTTP/1.1 Сообщения о перенаправлениях 300 Multiple Choice

«Множественный выбор». Этот код ответа присылается, когда запрос имеет
более чем один из возможных ответов. И User-agent или пользователь
должен выбрать один из ответов. Не существует стандартизированного
способа выбора одного из полученных ответов.

HTTP/1.0 и выше 301 Moved Permanently

«Перемещён на постоянной основе». Этот код ответа значит, что URI
запрашиваемого ресурса был изменён. Возможно, новый URI будет
предоставлен в ответе.

HTTP/0.9 и выше 302 Found

«Найдено». Этот код ответа значит, что запрошенный ресурс
временно изменён. Новые изменения в URI могут быть доступны в
будущем. Таким образом, этот URI, должен быть использован клиентом в
будущих запросах.

HTTP/0.9 и выше 303 See Other «Просмотр других ресурсов». Этот код ответа присылается, чтобы
направлять клиента для получения запрашиваемого ресурса в другой URI с
запросом GET. HTTP/0.9 и 1.1 304 Not Modified «Не модифицировано». Используется для кеширования. Это код ответа
значит, что запрошенный ресурс не был изменён. Таким образом, клиент
может продолжать использовать кешированную версию ответа. HTTP/0.9 и выше 305 Use Proxy «Использовать прокси». Это означает, что запрошенный ресурс должен быть
доступен через прокси. Этот код ответа в основном не поддерживается из
соображений безопасности. Только HTTP/1.1 306 Switch Proxy Больше не использовать. Изначально подразумевалось, что » последующие
запросы должны использовать указанный прокси.» Только HTTP/1.1 307 Temporary Redirect «Временное перенаправление». Сервер отправил этот ответ, чтобы клиент
получил запрошенный ресурс на другой URL-адрес с тем же методом, который
использовал предыдущий запрос. Данный код имеет ту же семантику, что код
ответа 302 Found, за исключением того, что агент
пользователя не должен изменять используемый метод HTTP: если в первом
запросе использовался POST, то во втором запросе также
должен использоваться POST. Только HTTP/1.1 308 Permanent Redirect

«Перенаправление на постоянной основе». Это означает, что ресурс
теперь постоянно находится в другом URI, указанном в заголовке
Location: HTTP Response. Данный код ответа имеет ту же
семантику, что и код ответа 301 Moved Permanently, за
исключением того, что агент пользователя не должен изменять
используемый метод HTTP: если POST использовался в первом
запросе, POST должен использоваться и во втором запросе.

Примечание: Это экспериментальный код ответа,
Спецификация которого в настоящее время находится в черновом виде.

draft-reschke-http-status-308 Клиентские 400 Bad Request «Плохой запрос». Этот ответ означает, что сервер не понимает запрос
из-за неверного синтаксиса. HTTP/0.9 и выше 401 Unauthorized «Неавторизованно». Для получения запрашиваемого ответа нужна
аутентификация. Статус похож на статус 403, но,в этом случае,
аутентификация возможна. HTTP/0.9 и выше 402 Payment Required «Необходима оплата». Этот код ответа зарезервирован для будущего
использования. Первоначальная цель для создания этого кода была в
использовании его для цифровых платёжных систем(на данный момент не
используется). HTTP/0.9 и 1.1 403 Forbidden «Запрещено». У клиента нет прав доступа к содержимому, поэтому сервер
отказывается дать надлежащий ответ. HTTP/0.9 и выше 404 Not Found «Не найден». Сервер не может найти запрашиваемый ресурс. Код этого
ответа, наверно, самый известный из-за частоты его появления в вебе. HTTP/0.9 и выше 405 Method Not Allowed «Метод не разрешён». Сервер знает о запрашиваемом методе, но он был
деактивирован и не может быть использован. Два обязательных метода,
GET и HEAD, никогда не должны быть
деактивированы и не должны возвращать этот код ошибки. Только HTTP/1.1 406 Not Acceptable

Этот ответ отсылается, когда веб сервер после выполнения
server-driven content negotiation, не нашёл контента, отвечающего критериям, полученным из user agent.

Только HTTP/1.1 407 Proxy Authentication Required Этот код ответа аналогичен коду 401, только аутентификация требуется для
прокси сервера. Только HTTP/1.1 408 Request Timeout Ответ с таким кодом может прийти, даже без предшествующего запроса. Он
означает, что сервер хотел бы отключить это неиспользуемое соединение.
Этот метод используется все чаще с тех пор, как некоторые браузеры,
вроде Chrome и IE9, стали использовать
HTTP механизмы предварительного соединения
для ускорения сёрфинга (смотрите баг 634278, будущей
реализации этого механизма в Firefox). Также учитывайте, что некоторые
серверы прерывают соединения не отправляя подобных сообщений. Только HTTP/1.1 409 Conflict

Этот ответ отсылается, когда запрос конфликтует с текущим состоянием
сервера.

Только HTTP/1.1 410 Gone

Этот ответ отсылается, когда запрашиваемый контент удалён с сервера.

Только HTTP/1.1 411 Length Required

Запрос отклонён, потому что сервер требует указание заголовка
Content-Length, но он не указан.

Только HTTP/1.1 412 Precondition Failed Клиент указал в своих заголовках условия, которые сервер не может
выполнить Только HTTP/1.1 413 Request Entity Too Large

Размер запроса превышает лимит, объявленный сервером. Сервер может
закрыть соединение, вернув заголовок Retry-After

Только HTTP/1.1 414 Request-URI Too Long URI запрашиваемый клиентом слишком длинный для того, чтобы сервер смог
его обработать Только HTTP/1.1 415 Unsupported Media Type Медиа формат запрашиваемых данных не поддерживается сервером, поэтому
запрос отклонён Только HTTP/1.1 416 Requested Range Not Satisfiable Диапазон указанный заголовком запроса Range не может быть
выполнен; возможно, он выходит за пределы переданного URI Только HTTP/1.1 417 Expectation Failed Этот код ответа означает, что ожидание, полученное из заголовка запроса
Expect, не может быть выполнено сервером. Только HTTP/1.1 Серверные 500 Internal Server Error «Внутренняя ошибка сервера». Сервер столкнулся с ситуацией, которую он
не знает как обработать. HTTP/0.9 и выше 501 Not Implemented «Не реализовано». Метод запроса не поддерживается сервером и не может быть
обработан. Единственные методы, которые сервера должны поддерживать (и,
соответственно, не должны возвращать этот код) — GET и
HEAD. HTTP/0.9 и выше 502 Bad Gateway «Плохой шлюз». Эта ошибка означает что сервер, во время работы в
качестве шлюза для получения ответа, нужного для обработки запроса,
получил недействительный (недопустимый) ответ. HTTP/0.9 и выше 503 Service Unavailable «Сервис недоступен». Сервер не готов обрабатывать запрос. Зачастую
причинами являются отключение сервера или то, что он перегружен.
Обратите внимание, что вместе с этим ответом удобная для
пользователей(user-friendly) страница должна отправлять объяснение
проблемы. Этот ответ должен использоваться для временных условий и
Retry-After: HTTP-заголовок должен, если возможно,
содержать предполагаемое время до восстановления сервиса. Веб-мастер
также должен позаботиться о заголовках, связанных с кешем, которые
отправляются вместе с этим ответом, так как эти ответы, связанные с
временными условиями, обычно не должны кешироваться. HTTP/0.9 и выше 504 Gateway Timeout Этот ответ об ошибке предоставляется, когда сервер действует как шлюз и
не может получить ответ вовремя. Только HTTP/1.1 505 HTTP Version Not Supported «HTTP-версия не поддерживается». HTTP-версия, используемая в запросе, не
поддерживается сервером. Только HTTP/1.1

HTTP, Hypertext Transfer Protocol, is the method by which clients (i.e. you) and servers communicate. When someone clicks a link, types in a URL or submits out a form, their browser sends a request to a server for information. It might be asking for a page, or sending data, but either way, that is called an HTTP Request. When a server receives that request, it sends back an HTTP Response, with information for the client. Usually, this is invisible, though I’m sure you’ve seen one of the very common Response codes — 404, indicating a page was not found. There are a fair few more status codes sent by servers, and the following is a list of the current ones in HTTP 1.1, along with an explanation of their meanings.

A more technical breakdown of HTTP 1.1 status codes and their meanings is available at http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html. There are several versions of HTTP, but currently HTTP 1.1 is the most widely used.

Informational

• 100 — Continue
  A status code of 100 indicates that (usually the first) part of a request has been received without any problems, and that the rest of the request should now be sent.
• 101 — Switching Protocols
  HTTP 1.1 is just one type of protocol for transferring data on the web, and a status code of 101 indicates that the server is changing to the protocol it defines in the «Upgrade» header it returns to the client. For example, when requesting a page, a browser might receive a statis code of 101, followed by an «Upgrade» header showing that the server is changing to a different version of HTTP.

Successful

• 200 — OK
  The 200 status code is by far the most common returned. It means, simply, that the request was received and understood and is being processed.
• 201 — Created
  A 201 status code indicates that a request was successful and as a result, a resource has been created (for example a new page).
• 202 — Accepted
  The status code 202 indicates that server has received and understood the request, and that it has been accepted for processing, although it may not be processed immediately.
• 203 — Non-Authoritative Information
  A 203 status code means that the request was received and understood, and that information sent back about the response is from a third party, rather than the original server. This is virtually identical in meaning to a 200 status code.
• 204 — No Content
  The 204 status code means that the request was received and understood, but that there is no need to send any data back.
• 205 — Reset Content
  The 205 status code is a request from the server to the client to reset the document from which the original request was sent. For example, if a user fills out a form, and submits it, a status code of 205 means the server is asking the browser to clear the form.
• 206 — Partial Content
  A status code of 206 is a response to a request for part of a document. This is used by advanced caching tools, when a user agent requests only a small part of a page, and just that section is returned.

Redirection

• 300 — Multiple Choices
  The 300 status code indicates that a resource has moved. The response will also include a list of locations from which the user agent can select the most appropriate.
• 301 — Moved Permanently
  A status code of 301 tells a client that the resource they asked for has permanently moved to a new location. The response should also include this location. It tells the client to use the new URL the next time it wants to fetch the same resource.
• 302 — Found
  A status code of 302 tells a client that the resource they asked for has temporarily moved to a new location. The response should also include this location. It tells the client that it should carry on using the same URL to access this resource.
• 303 — See Other
  A 303 status code indicates that the response to the request can be found at the specified URL, and should be retrieved from there. It does not mean that something has moved — it is simply specifying the address at which the response to the request can be found.
• 304 — Not Modified
  The 304 status code is sent in response to a request (for a document) that asked for the document only if it was newer than the one the client already had. Normally, when a document is cached, the date it was cached is stored. The next time the document is viewed, the client asks the server if the document has changed. If not, the client just reloads the document from the cache.
• 305 — Use Proxy
  A 305 status code tells the client that the requested resource has to be reached through a proxy, which will be specified in the response.
• 307 — Temporary Redirect
  307 is the status code that is sent when a document is temporarily available at a different URL, which is also returned. There is very little difference between a 302 status code and a 307 status code. 307 was created as another, less ambiguous, version of the 302 status code.

Client Error

• 400 — Bad Request
  A status code of 400 indicates that the server did not understand the request due to bad syntax.
• 401 — Unauthorized
  A 401 status code indicates that before a resource can be accessed, the client must be authorised by the server.
• 402 — Payment Required
  The 402 status code is not currently in use, being listed as «reserved for future use».
• 403 — Forbidden
  A 403 status code indicates that the client cannot access the requested resource. That might mean that the wrong username and password were sent in the request, or that the permissions on the server do not allow what was being asked.
• 404 — Not Found
  The best known of them all, the 404 status code indicates that the requested resource was not found at the URL given, and the server has no idea how long for.
• 405 — Method Not Allowed
  A 405 status code is returned when the client has tried to use a request method that the server does not allow. Request methods that are allowed should be sent with the response (common request methods are POST and GET).
• 406 — Not Acceptable
  The 406 status code means that, although the server understood and processed the request, the response is of a form the client cannot understand. A client sends, as part of a request, headers indicating what types of data it can use, and a 406 error is returned when the response is of a type not i that list.
• 407 — Proxy Authentication Required
  The 407 status code is very similar to the 401 status code, and means that the client must be authorised by the proxy before the request can proceed.
• 408 — Request Timeout
  A 408 status code means that the client did not produce a request quickly enough. A server is set to only wait a certain amount of time for responses from clients, and a 408 status code indicates that time has passed.
• 409 — Conflict
  A 409 status code indicates that the server was unable to complete the request, often because a file would need to be editted, created or deleted, and that file cannot be editted, created or deleted.
• 410 — Gone
  A 410 status code is the 404’s lesser known cousin. It indicates that a resource has permanently gone (a 404 status code gives no indication if a resource has gine permanently or temporarily), and no new address is known for it.
• 411 — Length Required
  The 411 status code occurs when a server refuses to process a request because a content length was not specified.
• 412 — Precondition Failed
  A 412 status code indicates that one of the conditions the request was made under has failed.
• 413 — Request Entity Too Large
  The 413 status code indicates that the request was larger than the server is able to handle, either due to physical constraints or to settings. Usually, this occurs when a file is sent using the POST method from a form, and the file is larger than the maximum size allowed in the server settings.
• 414 — Request-URI Too Long
  The 414 status code indicates the the URL requested by the client was longer than it can process.
• 415 — Unsupported Media Type
  A 415 status code is returned by a server to indicate that part of the request was in an unsupported format.
• 416 — Requested Range Not Satisfiable
  A 416 status code indicates that the server was unable to fulfill the request. This may be, for example, because the client asked for the 800th-900th bytes of a document, but the document was only 200 bytes long.
• 417 — Expectation Failed
  The 417 status code means that the server was unable to properly complete the request. One of the headers sent to the server, the «Expect» header, indicated an expectation the server could not meet.

Server Error

• 500 — Internal Server Error
  A 500 status code (all too often seen by Perl programmers) indicates that the server encountered something it didn’t expect and was unable to complete the request.
• 501 — Not Implemented
  The 501 status code indicates that the server does not support all that is needed for the request to be completed.
• 502 — Bad Gateway
  A 502 status code indicates that a server, while acting as a proxy, received a response from a server further upstream that it judged invalid.
• 503 — Service Unavailable
  A 503 status code is most often seen on extremely busy servers, and it indicates that the server was unable to complete the request due to a server overload.
• 504 — Gateway Timeout
  A 504 status code is returned when a server acting as a proxy has waited too long for a response from a server further upstream.
• 505 — HTTP Version Not Supported
  A 505 status code is returned when the HTTP version indicated in the request is no supported. The response should indicate which HTTP versions are supported.

11 May 2004   |   development, http, reference, web, codes, status, apache, webdev, for beginners