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Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Key Applications and Application Protocols
           9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)
                9  TCP/IP World Wide Web (WWW, "The Web") and the Hypertext Transfer Protocol (HTTP)
                     9  TCP/IP Hypertext Transfer Protocol (HTTP)
                          9  HTTP Messages, Message Formats, Methods and Status Codes

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HTTP Status Code Format, Status Codes and Reason Phrases
(Page 3 of 4)

Status Codes and Reason Phrases

Table 275 lists in numerical order the status codes defined by the HTTP/1.1 standard, along with the “standard” reason phrase and a brief description of each:

Table 275: HTTP Status Codes

Status Code

Reason Phrase




Client should continue sending its request. This is a special status code; see below for details.


Switching Protocols

The client has used the Upgrade header to request the use of an alternative protocol and the server has agreed.



Generic successful request message response. This is the code sent most often when a request is filled normally.



The request was successful and resulted in a resource being created. This would be a typical response to a PUT method.



The request was accepted by the server but has not yet been processed. This is an intentionally “non-commital” response that does not tell the client whether or not the request will be carried out; the client determines the eventual disposition of the request in some unspecified way. It is used only in special circumstances.


Non-Authoritative Information

The request was successful, but some of the information returned by the server came not from the original server associated with the resource but from a third party.


No Content

The request was successful, but the server has determined that it does not need to return to the client an entity body.


Reset Content

The request was successful; the server is telling the client that it should reset the document from which the request was generated so that a duplicate request is not sent. This code is intended for use with forms.


Partial Content

The server has successfully fulfilled a partial GET request. See the topic on methods for more details on this, as well as the description of the Range header.


Multiple Choices

The resource is represented in more than one way on the server. The server is returning information describing these representations, so the client can pick the most appropriate one, a process called agent-driven negotiation.


Moved Permanently

The resource requested has been moved to a new URL permanently. Any future requests for this resource should use the new URL.

This is the proper method of handling situations where a file on a server is renamed or moved to a new directory. Most people don't bother setting this up, which is why URLs “break” so often, resulting in 404 errors as discussed below.



The resource requested is temporarily using a different URL. The client should continue to use the original URL. See code 307.


See Other

The response for the request can be found at a different URL, which the server specifies. The client must do a fresh GET on that URL to see the results of the prior request.


Not Modified

The client sent a conditional GET request, but the resource has not been modified since the specified date/time, so the server has not sent it.


Use Proxy

To access the requested resource, the client must use a proxy, whose URL is given by the server in its response.



Defined in an earlier (draft?) version of HTTP and no longer used.


Temporary Redirect

The resource is temporarily located at a different URL than the one the client specified.

Note that 302 and 307 are basically the same status code. 307 was created to clear up some confusion related to 302 that occurred in earlier versions of HTTP (which I'd rather not get into!)


Bad Request

Server says, “huh?” J Generic response when the request cannot be understood or carried out due to a problem on the client's end.



The client is not authorized to access the resource. Often returned if an attempt is made to access a resource protected by a password or some other means without the appropriate credentials.


Payment Required

This is reserved for future use. Its mere presence in the HTTP standard has caused a lot of people to scratch their chins and go “hmm…” J



The request has been disallowed by the server. This is a generic “no way” response that is not related to authorization. For example, if the maintainer of Web site blocks access to it from a particular client, any requests from that client will result in a 403 reply.


Not Found

The most common HTTP error message, returned when the server cannot locate the requested resource. Usually occurs due to either the server having moved/removed the resource, or the client giving an invalid URL (misspellings being the most common cause.)


Method Not Allowed

The requested method is not allowed for the specified resource. The response includes an Allow header that indicates what methods the server will permit.


Not Acceptable

The client sent a request that specifies limitations that the server cannot meet for the specified resource. This error may occur if an overly-restrictive list of conditions is placed into a request such that the server cannot return any part of the resource.


Proxy Authentication Required

Similar to 401, but the client must first authenticate itself with the proxy.


Request Timeout

The server was expecting the client to send a request within a particular time frame and the client didn't send it.



The request could not be filled because of a conflict of some sort related to the resource. This most often occurs in response to a PUT method, such as if one user tries to PUT a resource that another user has open for editing, for example.



The resource is no longer available at the server, which does not know its new URL. This is a more specific version of the 404 code that is used only if the server knows that the resource was intentionally removed. It is seen rarely (if ever) compared to 404.


Length Required

The request requires a Content-Length header field and one was not included.


Precondition Failed

Indicates that the client specified a precondition in its request, such as the use of an If-Match header, which evaluated to a false value. This indicates that the condition was not satisfied so the request is not being filled. This is used by clients in special cases to ensure that they do not accidentally receive the wrong resource.


Request Entity Too Large

The server has refused to fulfill the request because the entity that the client is requesting is too large.


Request-URI Too Long

The server has refused to fulfill the request because the URL specified is longer than the server can process. This rarely occurs with properly-formed URLs but may be seen if clients try to send gibberish to the server.


Unsupported Media Type

The request cannot be processed because it contains an entity using a media type the server does not support.


Requested Range Not Satisfiable

The client included a Range header specifying a range of values that is not valid for the resource. An example might be requesting bytes 3,000 through 4,000 of a 2,400-byte file.


Expectation Failed

The request included an Expect header that could not be satisfied by the server.


Internal Server Error

Generic error message indicating that the request could not be fulfilled due to a server problem.


Not Implemented

The server does not know how to carry out the request, so it cannot satisfy it.


Bad Gateway

The server, while acting as a gateway or proxy, received an invalid response from another server it tried to access on the client's behalf.


Service Unavailable

The server is temporarily unable to fulfill the request for internal reasons. This is often returned when a server is overloaded or down for maintenance.


Gateway Timeout

The server, while acting as a gateway or proxy, timed out while waiting for a response from another server it tried to access on the client's behalf.


HTTP Version Not Supported

The request used a version of HTTP that the server does not understand.

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