File Transfer Protocol: It's Definition and Uses
Since the original FTP specification was written in 1971, the first FTP clients were completely command-line programs, as they were developed before operating systems adopted GUIs (i.e., Graphical User Interfaces). Nevertheless, there have been countless GUI FTP clients designed for desktops, servers, and even mobile devices. This guide has all of the required information to understand FTP and its usage. We have divided the guide into two parts, so the first one has all of the necessary details on FTP, and the other has its usage-related details.
What is FTP
File Transfer Protocol is a standard network protocol used to transfer computer files between a client and a server across a computer network. Users can use FTP through a command-line interface such as DOS in Windows and Terminal in Linux & macOS. If that is not your cup of tea, then you can also use one of many FTP clients available online, some even for free. Some browsers also allow you to download files using the protocol. It is possible to transfer any file with FTP, and in some cases, it is even faster than HTTP. For example, here is a good article about how to install FTP Server on Ubuntu Server.
To login into an FTP server, you will need to enter a username and password and the port number (when logging in using the command-line interface). The FTP protocol is handled by ports number 20 and 21 by default. There is also a possibility to anonymously access FTP servers, on which we will elaborate in the following paragraphs.
Most public servers offer you the possibility of login in and download files via FTP by connecting anonymously. This does not mean that you are 100% anonymous, but that you use "anonymous" as the username and, in most cases, your email address as the password. You do not need to have an existing account to access the FTP server.
ASCII and Binary
There are two different forms that file transfers use over FTP: ASCII and binary. ASCII (i.e., American Standard Code for Information Interchange) is a 7-bit character set that contains 128 characters. Any file that is text-based (e.g. HTML, .txt, PostScript files, etc.) is an ASCII file.
On the other hand, we have binary files, which have a different structure and require different transfer types. These include images, applications, algorithmically generated packages such as .zip, and much more.
Nowadays, with an enormous variety of FTP clients available, almost any one of them will automatically detect the transfer mode based on the files you have chosen. Most clients will run in binary by default, using ASCII only when it is required. They do so because users can transfer both ASCII and binary files through the binary method. However, if a binary file is transferred through ASCII, it will be corrupted. There is one small exception to the rule as mentioned above. You must transfer CGI scripts through ASCII; otherwise, they will not work.
Even though we highly recommend the use of an FTP client, sometimes a web browser might suffice. Once directed to an FTP server, you will have to log in, and you will be able to browse the server and download the files. Please note that using an FTP browser offers minimal functionality and has a much greater security risk than an FTP client.
There are different types of FTP server and FTP clients, so here is the list of the most used server and clients:
Most used FTP servers
Most Used FTP Clients
How does FTP Work
At the initial stage, an FTP connection requires two parties to establish and communicate on a specific network. A user requires permission to provide credentials to an FTP server, but some public FTP servers don't need any credentials for accessing the files.
In the procedure for establishing an FTP connection, two different communication channels, command channels and data channels, are needed. Command channels work to initiate a specific response and instructions. On the other side, data channels work as a platform where data distribution occurs.
An authorized user can use a protocol for requesting to make changes on the server for transferring files, and for this transfer procedure, the server will allow access. This session is called an active connection mode where users request changes and the server grant access. Active mode distribution may face issues when a firewall protects the system of a user. Hence this firewall doesn't allow unauthorized sessions from any outer party.
A passive mode is used when a user faces any issue, so a user needs to establish a command channel and data channel for it. After setting both channels, passive mode requests the server to listen instead of attempting to connect back to users.
How to Use FTP
There are three different ways to establish an FTP connection quickly, and they are:
Having a little bit of programming knowledge can create convenience for the user because there are Command-line FTP for macOS, Windows, and Linux. Many developers prefer this method instead of others for transferring their files in FTP.
Graphical FTP Programs
This approach works to simplify a file transfer, as a user can easily drag and drop the files from one Window to another. In these programs, the user must provide an FTP host, username, and password to access it.
This approach is easy because users can use a web browser for connection to their FTP address. Many users prefer the web browser approach as it is easier and more beneficial to access huge directories on a server. However, it is a little bit slower and less reliable than a dedicated FTP program.
So it was the brief of FTP with all of the little details around it, and we hope that our given information will be helpful for you. As we have mentioned earlier, the full form of FTP is File Transfer Protocol, which is used for transferring files from client to server. We have also included details on the usage and working of FTP so that you can get complete information through our guide.