What Is FTP? FTP Clients and FTP Ports Explained

If you have ever downloaded a file from a website, the FTP is what allowed you to do so. Businesses and web developers use this popular protocol to securely upload and share large files with ease. In this article, we'll discuss the FTP meaning and basics, including what it's used for, how it works, the FTP ports involved, and other considerations.

What does FTP stand for?

FTP stands for File Transfer Protocol. It's a shorter acronym for the standard communication protocol for sending files across the Internet.

What is FTP?

File Transfer Protocol (FTP) is a network protocol used to transfer files between computers over a TCP (transmission control protocol) or UDP (user datagram protocol) connection, or, essentially, the Internet. Basically, it provides for a way for computers to transfer files while both connected to a server. Its original use served as a way to transfer files from physical device to physical device, but now it mostly operates through cloud servers.

There are two main uses for File Transfer Protocol: file sharing and web development. Businesses use File Transfer Protocol to easily transfer sensitive files between computers. Web developers use File Transfer Protocol to upload and download files to their websites' servers.

FIle transfer protocol (FTP) graphic illustration

File Transfer Protocol is capable of using TCP ports or UDP ports to establish data connections. Ports are crucial to the function of FTP, meaning if ports are not working properly, a port scanner should be used to check their accessibility.

How does FTP work?

File Transfer Protocol is a client-server protocol that computers use to transfer files over a network. For two parties to share files using FTP, the users need to use a web browser or FTP client to enter username and password credentials to the FTP server. Note that some servers lack password protection.

After establishing a connection, a complete data transfer requires two separate channels. The first channel, called the command channel, is used for the instructions and the response. The second channel is the data channel. This is where the transfer of files occurs.

The command channel uses TCP port 21, while the data channel uses TCP port 20.

Active mode versus passive mode

Active mode is the traditional connection type. With active mode, the server dictates which port number to use. While in passive mode, the client can choose which port to use.

The reason there are two modes is because of firewalls, which can block certain port numbers. For example, say your firewall blocks port 20 (the port used to transfer data). In this case, you could use passive mode to get around this block. With passive mode, your FTP client can change to a different port for the client and server to use to transfer the data.

Three ways to use File Transfer Protocol

There are three main ways to use File Transfer Protocol: the command line, a web browser, and through a dedicated client software.

  1. Through the command line. The first, and oldest, method is to use a command-line such as the Command prompt for Windows or Terminal for Mac/Linux. With this method, commands establish a connection to a File Transfer Protocol server port.
  2. Through a web browser. Another way is to use a web browser by typing "ftp.[web address].com" into the URL bar the same way you'd enter webpages. This method is helpful when attempting to upload or download large numbers of files.
  3. Through a dedicated client software. The last, and most common method, is to use a dedicated FTP client software. These are more reliable, faster, and more user-friendly than the other two methods. Popular free FTP clients providing FTP services include Cyberduck and FileZilla.

How to use an FTP client

To connect to an FTP server using an FTP client, you typically need to enter a username and password, host or server name, and FTP port number (data port 21). Once connected, File Transfer Protocol client interfaces usually allow you to drag and drop files to and from your hard drive into the server.

What is Secure File Transfer Protocol?

Traditional File Transfer Protocol operates with password protection. But connection security ends there. That's because the information sent is not encrypted over FTP, meaning it is vulnerable to interception. Creators of the protocol did not originally intend it to provide a secure channel to send and receive data. Thus, if a hacker were to intercept your transmission, they would be able to read everything with ease.

Secure File Transfer Protocol is the File Transfer Protocol, but with additional protective measures added on. It uses SSH, or secure shell, security and encryption to block port scanning and password sniffing, as detailed above. It necessitates server authentication as well, which keeps hackers from intercepting information during transfers.

SFTP as a security solution

To encrypt the data you send, you should use TCP port 22 instead of TCP port 21 when establishing the connection. This will establish a Secure File Transfer Protocol connection. Encrypting your files will greatly reduce the chance of hackers stealing your personal information.


You should now have a basic understanding of FTP, meaning File Transfer Protocol, as well as what it is used for and how it works. Users can use File Transfer Protocol to transfer files to each other via a server. FTP clients make using File Transfer Protocol much easier to efficiently transfer larger numbers of files.