Welcome to the exciting world of networking!
FTP and HTTP are the most popular protocols used on the Internet and most local networks. In order to understand how they work, you need to know a few basics on protocols and data communications.
Since you're new to networking, we will stick to the very basics in order to avoid confusing you.
Both FTP and HTTP are protocols used to send/receive application data. FTP as you already know is used to transfer data from one host to another, while HTTP is used to transfer web pages from servers to its clients (your Web browser.)
FTP and HTTP rely on other protocols – so called 'Transport Protocols' – to transport them from one host (computer) to another, and this is where TCP comes into the picture.
A transport protocol is like a train wagon - it simply carries data and doesn't know or care about what data it's carrying. This data can be FTP, HTTP or any other type.
The transport protocol makes sure that all HTTP and FTP data is sent to the correct host (computer) by utilizing special mechanisms built into the TCP protocol. These mechanisms have been designed to ensure the above process works in a reliable manner.
One of the most important features of TCP is that before it sends any data, I.E. a HTTP request (generated when you click on a link or request a Web site I.E. http://www.searchnetworking.com) it must make sure there is a connection to that server. This is called the 3-way handshake and is why TCP is also known as a "connection orientated protocol," meaning that it requires to establish a connection before sending any http or ftp data.
So, your should now start to realize that in order to understand how FTP and HTTP work, you need to know a bit more on how data communication works.
Since it would take a few pages to completely answer your question, I would strongly recommend you visit http:www.Firewall.cx. The site will help guide you through the material you need to learn in order to understand the new concepts you will be introduced to, give answers to your questions and also give you an insight on how other cool protocols work I.E. DNS, TFTP.
The world of networking is a big one, but also very interesting. The deeper you dive, the more fascinating things you will discover and the more you will come to love it :)
This was first published in July 2003