FTP is the protocol that every single web hosting server out there uses to enable its subscribers and users upload and download content between their servers. The servers are simply computers like the one you have at home, but substantially more powerful and with a lot more hard disk space. The reason they have so much disk space if because there may well be hundreds of users’ websites stored on that one machine, each one of those has the ability to connect to the server and transfer files using an FTP client. When ever you connect to your web host to do work on your website you are using FTP, a few people may be using SFTP but probably won’t be aware of it. Either way, you will be using a form of FTP!
FTP clients are simply programs that allow you to use all the commands available to the FTP protocol, such as upload, download, move, rename and many more. It is of course possible to do all this manually without the use of a GUI (Graphical User Interface), which is what commercial FTP clients provide you with like buttons and menus. Manual methods often involve a command line interface where the user types the FTP commands directly, telling the server exactly what to do. For most people, this would take to long to learn and would most likely not be worth learning if they just want to do the odd file upload or download! Graphical based FTP clients take away all those complexities giving you simple buttons to click on that execute the complicated commands for you. A new generation of FTP convenience has dawned upon us and that comes in the form of web based FTP clients. These are simply online interfaces or small programs that let you access your ftp/web server from a website. If you are going to use this kind of service make sure the website hosting the web based FTP client is trustworthy, as you have to enter in your login credentials to gain access to your FTP space. If it is a malicious website, it is very easy for them to steal that information from you!
Public FTP servers let you log into them with no user credentials what so ever and you are considered an anonymous user. Paid web hosting and ftp hosting services do not allow anonymous logins, as they are obviously a serious breach of security! Even if anonymous logins are permitted, an anonymous user will not be able to do any file operations what so ever. They are simply allowed to view the contents of the server only. The concept of anonymous user access is diminishing because it is becoming more and more useless as well as a security risk, so most administrators don’t allow it. Corporate servers and servers that hold confidential information will most likely use SFTP (Secure File Transfer Protocol) rather than just FTP (or at least they should!), because all instructions and activity information is made private and not viewable by the public or anyone else. Such information can be used by certain resourceful individuals to crack passwords and perform a whole host of other damaging activities.