100 Continue

101 Switching Protocols

These codes are reserved for future versions

200 OK

201 Created

202 Accepted

203 Non-Authoritative Information

204 No Content

205 Reset Content

206 Partial Content

The usual response to a GET

The correct response to a PUT/POST

The server accepted the data, but did not do anything with it yet (for example in case of an upload)

Usually sent by a proxy

This is a good way to tell a client the page has not been updated

This tells the client to reset all form fields

This is implemented in HTTP 1.1 as a response for a range request

300 Multiple Choice

301 Moved Permanently

302 Moved Temporarily

303 See other

304 Not modified

305 Use Proxy

307 Temporary Redirect

Give the client a choice where to fetch the data, for example, for mirrors

Tell the browser to redirect and update bookmarks

Tell the browser to redirect for now. Refer to Chapter 2 for further information.

Redirects a POST request to a GET request.

Means the same as 204, but answers an If-Modified request

Tells the client to connect through a proxy server

Sent if a client denies a 302

400 Bad Request

401 Access Denied

402 Payment required

403 Forbidden

404 Not found

405 Method not allowed

406 Not Acceptable

407 Proxy Authentication required

408 Timeout

409 Conflict

410 Gone

411 Length Required

412 Precondition Failed

413 Request Entity Too Large

414 Request URL Too Long

415 Unsupported Media Type

416 Request Range Not Satisfiable

417 Expectation Failed

The request does not conform to the HTTP syntax

Sent by mod_auth; initiates HTTP authorization. Refer to Chapter 7 for further information

For micropayment (not implemented)

If the server could not access a file or if the HTTP authorization failed

The file was not found on the server. Refer to server.error-handler-404 in Chapter 2.

The client should try a different method

The request was denied for formal reasons

A HTTP proxy should be used for authenticating the client

Self descriptive, isn't it? Refer to server.timeout in Chapter 2

A file to read/write is locked.

The page has moved to an unknown location, so a redirect is not possible.

The server requires a Content-Length header on POST request

A Precondition specified in the request could not be satisfied

Some of the request entities were too large to fit in the buffers; Bad luck.

The URL did not fit in the buffer so the request was probably bad anyway.

The client asked a MIME type that the server did not know

We got a HTTP 1.1 range request with a negative or overflowing range

The client sent an Expect header with the request, but we could not fulfill it

500 Internal Server Error

501 Not Implemented

502 Bad Gateway

503 Service Unavailable

504 Gateway Timeout

505 HTTP Version Not Supported

Usually the result of a CGI script gone wrong

Sent out for a non-HTTP1.1 request—anything but GET, HEAD, or POST

Another server on the backend returned an error

There was an error on the backend site, but it will be fixed real soon now

The request was proxied to another server, but the proxied request timed out

Lighttpd will send this for any version above 1.1