184.108.40.206.6 Echo Response
An echo response is used in the proxy discovery protocol sequence. This response is sent by an inbound or outbound proxy as an HTTP response to the echo HTTP request. The same echo response is sent by both inbound and outbound proxies.
The header fields of the HTTP response are as follows:
Connection: Inbound and outbound proxies SHOULD set this to Keep-Alive. Clients MUST ignore this header field.
Content-Length: Inbound and outbound proxies MUST set this field to 20. Clients MUST ignore this header field.
Content-Type: Inbound and outbound proxies MUST set this header field to the string literal "application/rpc". Clients SHOULD ignore this header field.
Status Line: [RFC2616] section 6.1 specifies that the status line be composed of three nonspace subfields:
HTTP-Version: The HTTP protocol version of the HTTP server. This protocol does not require any particular HTTP version. Any HTTP version that is 1.0 or higher SHOULD be accepted by implementations of this protocol.
Reason-Phrase: MUST be Success.
Status-Code: MUST be 200.
Implementations SHOULD respond with the Status Line as specified above. It is not a requirement of this protocol for implementations to use the status-code field to indicate errors, though implementations MAY do so.