Hypertext Transfer Protocol (HTTP)

Hypertext Transfer Protocol is a standard Internet protocol that specifies the client/server interaction processes between Web browsers and Web servers.

What is Hypertext Transfer Protocol?

A standard Internet protocol that specifies the client/server interaction processes between Web browsers such as Microsoft Internet Explorer and Web servers such as Microsoft Internet Information Services (IIS).

How it works

The original Hypertext Transfer Protocol (HTTP) 1.0 protocol is a stateless protocol whereby a Web browser forms a connection with a Web server, downloads the appropriate file, and then terminates the connection.

The browser usually requests a file using an HTTP GET method request on TCP port 80, which consists of a series of HTTP request headers that define the transaction method (GET, POST, HEAD, and so on) and indicates to the server the capabilities of the client. The server responds with a series of HTTP response headers that indicate whether the transaction is successful, the type of data being sent, the type of server, and finally the requested data.

IIS 4 supports a new version of this protocol called HTTP 1.1, which has new features that make it more efficient. These new features include the following:

  • Persistent connections:
    An HTTP 1.1 server can keep TCP connections open after a file has been transferred, eliminating the need for a connection to be opened and closed each time a file is transferred, as is the case with HTTP 1.0.

     

  • Pipelining:
    This is a process whereby an HTTP 1.1 client can send multiple Internet Protocol (IP) packets to the server without waiting for the server to respond to each packet.

     

  • Buffering:
    This process allows several HTTP requests by the client to be buffered into a single packet and sent to the server, which results in faster transfer times because fewer and larger packets are used.

     

  • Host headers:
    This feature enables an HTTP 1.1–compliant Web server to host multiple Web sites using a single IP address.

     

  • Http put and http delete commands:
    These commands enable Web browsers to upload and delete files from Web servers using HTTP.

     

NOTE

If you want to use the HTTP 1.1 features of Microsoft Internet Information Server 4, your clients must be running an HTTP 1.1–compliant browser such as Microsoft Internet Explorer 4.

NOTE

Don’t confuse HTTP with HTML! HTTP is the protocol through which Web servers communicate with Web browsers. It is a control language for passing commands between clients and servers. HTML is Hypertext Markup Language, the language for constructing Web pages (the actual content passed from Web servers to Web clients in an HTTP request).

TIP

You can view the HTTP headers in HTTP requests and responses by using the full version of Network Monitor, a tool included with Microsoft Systems Management Server (SMS). Set your capture filter to capture HTTP protocol packets, and then connect to the Internet and browse some Web sites to generate HTTP traffic.

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