With the advent of the Internet era, writing programs based on Internet protocols has become commonplace, so I've devoted five chapters to this topic. This chapter focuses on low-level socket programming and Internet protocols, Chapter 20 is devoted to server-side web programming, Chapter 21 covers IntraWeb, and Chapters 22 and 23 discuss XML and web services.
In this chapter I'll begin by looking at the sockets technology in general; then I'll move to the use of the Internet Direct (Indy) components supporting both low-level socket programming and the most common Internet protocols. I will introduce some elements of the HTTP protocol, leading up to building HTML files from database data.
Although you probably just want to use a high-level protocol, the discussion of Internet programming starts from the core concepts and low-level applications. Understanding TCP/ IP and sockets will help you grasp most of the other concepts more easily.