Host

The Host request header specifies the domain name of the server (for virtual hosting), and (optionally) the TCP port number on which the server is listening.

If no port is given, the default port for the service requested (e.g., "80" for an HTTP URL) is implied.

A Host header field must be sent in all HTTP/1.1 request messages. A 400 (Bad Request) status code will be sent to any HTTP/1.1 request message that lacks a Host header field or contains more than one.

Header type	Request header
Forbidden header name	yes

Syntax

Host: <host>:<port>

Directives

<host>

the domain name of the server (for virtual hosting).

<port> Optional

TCP port number on which the server is listening.

Examples

Host: developer.cdn.mozilla.net

Specifications

Specification	Title
RFC 7230, section 5.4: Host	Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing

Browser compatibility

See also

• 400