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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  TCP/IP World Wide Web (WWW, "The Web") and the Hypertext Transfer Protocol (HTTP)                      9  TCP/IP Hypertext Transfer Protocol (HTTP)

HTTP Persistent Connection Establishment, Management and Termination 1 HTTP Generic Message Format

As we saw in the operational overview of the Hypertext Transfer Protocol, HTTP is entirely oriented around the sending of client requests and server responses. These take the form of HTTP messages sent between clients and servers. As with all protocols, HTTP uses a special format that dictates the structure of both client request messages and server response messages; understanding how these messages work is a big part of comprehending HTTP as a whole.

In this section I describe the messages used by HTTP and the specific commands and responses issued by clients and servers. I begin with a look at the generic HTTP message format and the major components of every HTTP message. I then discuss the specific formats used for both requests and responses. I explain the different types of HTTP methods (commands) used in client requests, and the HTTP status codes used in server replies.

HTTP Persistent Connection Establishment, Management and Termination 1 HTTP Generic Message Format