Host Header

Table of Content

• Syntax
• Directives
• Examples
• Browser Compatibility
• How to modify Host header

In the HTTP protocol, the Host header field specifies the domain name of the server (for virtual hosting), and (optionally) the TCP port number on which the server is listening. The Host field value is a string representing the server's authority. It plays a crucial role in HTTP/1.1 to allow a single server to host multiple domains or interfaces.

Syntax

Host: <host>:<port>Copy

Directives

Host : The domain name of the server.

Port : (Optional) The TCP port number where the server is listening.

Examples

Host: www.example.com
Host: www.example.com:8080Copy

Browser Compatibility

How to modify Host header

ModHeader is a Chrome extension that allows users to manipulate HTTP request headers.

To use ModHeader to modify the Host header:

1. Install and click on the ModHeader icon in the toolbar.
2. In the Request Headers section, click + to add a new header
3. Enter "Host" in the header name field, and the desired domain in the header value field

Modifying the Host header can be incredibly useful for testing server behavior (on servers supporting virtual hosting), routing, load balancing scenarios, SEO auditing (to assess response for different locations) and many more.