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)                           9  HTTP Message Headers

HTTP General Headers 1 2 3 4 HTTP Response Headers

HTTP request headers, as you might imagine, are used only in HTTP request messages, and serve a number of functions in them. 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, comprising over a dozen different types.

Allows the client to tell the server what Internet media types it is willing to accept in a response. The header may list several different MIME media types and subtypes that the client knows how to deal with. Each may be prepended with a “quality value” (“q” parameter) to indicate the client's preference. If this header is not specified, the default is for the server to assume any media type may be sent to the client. See the topics on entity media types and content negotiation for more information on how this header is used.

Similar to Accept, but specifies what character sets the client is willing to accept in a response, rather than what media types. Again, the listed charsets may use a “q” value, and again, the default if the header is omitted is for the client to accept any character set.

Similar to Accept and Accept-Charset, but specifies what content encodings the client is willing to accept. This is often used to control whether or not the server may send content in compressed form. (Remember that content codings are not the same as transfer encodings.)

Similar to the preceding Accept-type headers, but provides a list of language tags that indicate what languages the client supports or expects the server to use in its response.

HTTP General Headers 1 2 3 4 HTTP Response Headers