510 Not Extended

The HTTP 510 Not Extended server error response status code is sent when the client request declares an HTTP Extension (2774) that should be used to process the request, but the extension is not supported.

Status

510 Not Extended

Examples

Extension not supported

In the following example, a client sends a request with a mandatory extension specified in the C-MAN header. The Connection header specifies that these extensions are to be handled on a hop-by-hop basis. A proxy forwards the extended request, but the Connection header is stripped out in transit. Because the origin server doesn’t receive any information about the M-GET method, it sends a 510 in response:

M-GET /document HTTP/1.1
Host: example.com
C-Man: "http://www.example.org/"
Connection: C-Man

HTTP/1.1 510 Not Extended

Specifications

See also

• HTTP response status codes