Represents a parsed Host HTTP request header.
The domain name of the server (for virtual hosting), and the TCP port number on which the server is listening.
The port number may be omitted if the port is the standard port for the service requested.
Mandatory since HTTP/1.1.
Example
Host: en.wikipedia.org:8080
Host: en.wikipedia.org
RFC2616 Specification
The Host request-header field specifies the Internet host and port number of the resource being requested, as
obtained from the original URI given by the user or referring resource (generally an HTTP URL, as described in
section 3.2.2).
The Host field value MUST represent the naming authority of the origin server or gateway given by the original URL.
This allows the origin server or gateway to differentiate between internally-ambiguous URLs, such as the root "/" URL
of a server for multiple host names on a single IP address.
Host = "Host" ":" host [ ":" port ] ; Section 3.2.2
A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an
HTTP URL).
For example, a request on the origin server for <http://www.w3.org/pub/WWW/> would properly include:
GET /pub/WWW/ HTTP/1.1
Host: www.w3.org
A client MUST include a Host header field in all HTTP/1.1 request messages.
If the requested URI does not include an Internet host name for the service being requested, then the Host header
field MUST be given with an empty value.
An HTTP/1.1 proxy MUST ensure that any request message it forwards does contain an appropriate Host header field that
identifies the service being requested by the proxy.
All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request
message which lacks a Host header field.
See sections 5.2 and 19.6.1.1 for other requirements relating to Host.
See Also: