510 Not Extended

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: "https://www.example.org/"
Connection: C-Man

HTTP/1.1 510 Not Extended

• HTTP response status codes