What is HTTP?
The Hypertext Transfer Protocol is the foundation of the World Wide Web, and is used to load web pages using hypertext links. The hypertext transfer protocol is an application layer protocol designed to transfer information between networked devices and runs on top of other layers of the network protocol stack. A typical flow over HTTP involves a client machine making a request to a server, which then sends a response message.
HTTP is a stateless protocol, which means that each command runs independent of any other command. In the original spec, when a HTTP request was made in order to load a webpage the TCP connection used to make the request was not maintained. In newer versions of the HTTP protocol (HTTP 1.1 and above), persistent connection allows for multiple HTTP requests to pass over a persistent TCP connection, improving resource consumption. In the context of DoS or DDoS attacks, HTTP requests in large quantities can be used to mount an attack on a target device, and are considered part of application layer attacks or layer 7 attacks.