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Hypertext Transfer Protocol (HTTP).

HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it. This is the main reason that it is difficult to implement Web sites that react intelligently to user input. This shortcoming of HTTP is being addressed in a number of new technologies, including ActiveX, Java, JavaScript and cookies.

Complete Definition:

A client-server protocol used by  the World Wide Web (WWW) or any IP network (private net, intranet, extranet), for delivering content/applications to a client (typically client web browser).

HTTP protocol rides on top of a TCP Socket between client and web server (usually on TCP port 80 by default).

HTTP protocol has a set of natural "commands" which the caller sends in the request (i.e. from HTTP 1.1 (sometimes called HTTP Verbs) = GET, POST, PUT, DELETE, HEAD, OPTIONS) and an Uniform Resource Identifier (URI)  a "Server,Path, and File(resource)".  The URI tells the web server "which server, path, and file(resource)" and the HTTP verb tells the server what sort of request the user is requesting in each call.

The Web server will response with a "response header" where the "content type" of the "response" will be described (tells the client what sort of data the response will be and what to do with it) and of course the "response" itself.

Some HTTP responses are "cache-able" by Cache-engines, Content-engines, Proxies-caches, etc. and caching settings are in the server's "response header".

Wikapedia Definition for HTTP

Enabling HTTP Access to a Router:

Cisco includes an HTTP server in the IOS. You can enable this feature on a router, and then use any standard web browser to access the router instead of Telnet:

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#ip http server



You can also configure the HTTP server to use AAA authentication as follows:

Router(config)#ip http authentication aaa

If you want to restrict which devices are permitted to access the router's web interface use the access-class keyword as follow:

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#ip http server

Router(config)#access-list 10 permit

Router(config)#access-list 10 deny any

Router(config)#ip http access-class 10

If you are concerned about security of the HTTP protocol, but you still want the convenience of a web interface, you can opt instead for HTTPS


There are multiple HTTP standards:

HTTP1.0 - RFC 1945

HTTP1.1 - RFC 2616