510 Not Extended
The HTTP 510 Not Extendedserver error response status code is sent when the client request declares an HTTP Extension (RFC 2774) that should be used to process the request, but the extension is not supported.
Status
http
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:
http
M-GET /document HTTP/1.1 Host: example.com C-Man: "http://www.example.org/" Connection: C-Man http
HTTP/1.1 510 Not Extended Specifications
| Specification |
|---|
| RFC 2774 # section-7 |
