TCP/IP Guide

HTTP Request Headers

HTTP request headers, as you might imagine, are used only in HTTP Request messages, where they serve a number of functions. First, they allow the client to provide information about itself to the server. Second, they give additional details about the nature of the request that the client is making. Third, they allow the client to have greater control over how its request is processed and how (or even if) a response is returned by the server or intermediary.

This is the largest of the four categories of HTTP headers, containing more than a dozen different types, as follows:

Accept Allows the client to tell the server which Internet media types it is willing to accept in a response. The header may list several different Multipurpose ...