Understanding FTP File Transfer and Ports

Website dashboards can help you with different website processes – such as installing plugins, uploading and editing files, and even troubleshooting. However, there are limitations to what you can do in the dashboard. This is when you need to use FTP, or file transfer protocol. Files can be transferred between computers on a network using FTP. Accessing online software archives, file transfer between accounts, and file transfer between desktop computers are also possible with FTP.  

Looking for ways to manage your website services better? Then, it is important to understand how to use FTP effectively. From what FTP ports are, what FTP ports to use, and how they work. 

If you don’t know where to start, don’t worry. We’ll help you understand how to do the various FTP functions. 

What is FTP? 

FTP is the most commonly used protocol after HTTP. It’s designed for easy file transfer among computers – supporting the direct transfer of files over the network between an FTP client and a server. 

FTP opens two different connections that link the computers trying to communicate with each other. One connection is designated for the commands and replies that get transferred or sent between the two clients, while the other is used for handling data transfers. 

Additionally, FTP is capable of seamless large file size transfers – something website dashboards don’t offer – which can help businesses improve their workflow processes. 

What is an FTP Port? 

An FTP port is a communication endpoint allowing data transfers between a computer and a server. 

A computer’s operating system uses a specific number of FTP ports, which are necessary for software to connect through a network. 

They facilitate the quick exchange of files between the FTP client and server. The FTP port number ranges from 0 to 65535. So, there’s no definite port that FTP uses because the number can vary.  

There are different FTP port numbers available but the most common are as follows: 

  • Data Ports  

Data ports, as the name implies, are for transferring the actual data (uploading and downloading files) between the FTP client and server.  

A separate data port opens whenever a single file transfer happens. In most cases, during the control session, the client and server dynamically negotiate the FTP port number that is used. 

  • Control Ports  

Control ports are for transmitting control information. Among these include commands and login credentials to request a file transfer. The default control FTP port 21. 

Ftp Command Channel and Data Channel 

Any FTP session operates using two different channels, typically between the FTP client and server. These include a command channel for transmitting commands and a data channel for transferring data. 

Most often, the command channel is set to use FTP port 21. However, the FTP port for the data channel can differ depending on the data transfer mode. 

To demonstrate this; if you choose the active mode, for instance, the data channel will be FTP port 20, whereas the passive mode will use a random port. 

The key requirement to execute an FTP port connection through a client is the server’s name and login credentials. 

This establishes the FTP connection through FTP server port number 21. Otherwise, a different connection between a set of ports, in the FTP session mode, enables data transfer. 

The active mode here is where the server will open a connection from port 20 to the client’s control port. 

Also, note that the active mode is rarely used as it is incompatible with firewalls. The passive mode is where the FTP client asks which server port to connect to for data, followed by creating another connection to it.  

FTP Vulnerabilities and the Solution 

FTP Vulnerabilities and the Solution

At first, FTP didn’t prioritise security over the network as much and did not require user authentication to access files.  

But, given how security today is already a top priority, SFTP comes in. SFTP or Secure File Transfer Protocol is designed to protect confidential data and private information against various cyber-attacks. It offers end-to-end encryption between an FTP client and a server. It also uses a single port connection, port 22, for both control and data transfer. For a more secure connection, it relies on SSH for encryption and authentication procedures. 

Lastly, it also provides user/password authentication and a private/public key option to protect massive amounts of data. 


FTP can facilitate the seamless transfer of information between two computers, similar to what HTTP does through a web browser. 

The difference, however, is that FTP operates on two different TCP or Transmission Control Protocol port numbers – 20 and 21. To transfer the files successfully, both FTP ports 20 and 21 must both be open on the network. 

Because of its vulnerabilities, SFTP is an alternative that encrypts information with authentication requirements. Thus, securing a massive amount of data transfer. 

It offers businesses/organisations better and enhanced file transfer protection through the use of powerful, secure shell authentication. 

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