Today we are going to talk about what File Transfer Protocol (FTP) is and how does it work. Using the FTP file transfer protocol is one of the basic methods we can use to transfer files between computers over a TCP/IP network This method allows us to do transfer files in a fast way, even if they have a large size.
What is File Transfer Protocol (FTP)?
FTP stands for File Transfer Protocol. This method has been used since the 1970s. The default FTP ports on a computer are called port 20 and port 21, which are used to carry out this exchange or transfer process.
In a file transfer protocol one device functions as an FTP client and the other acts like an FTP server. The client is the one that is responsible for accessing another computer. An FTP client is, therefore, software that allows us to use this protocol to send or transfer files using the ports (control and data transport) of our computer or server. The client uses this FTP port for control and data transport.
What is FTP used for?
As we have said, the FTP protocol is used to transfer files. They allow us to transfer files in a fast and easy way. There is no limit considering the file size. And this method offers us great security as long as we use protocols like, SFTPL, SSL or SSH, for example.
How to connect to an FTP client?
There are several different programs that we can use to connect to a server and one of them is called FileZilla, it can be downloaded for free. It is one of the most popular solutions out there and we can download it from their website. When we have FileZilla on our computer we will see a series of fillable fields at the top such as server, username, password, and port. Simply type the IP address or domain of the FTP server to which you are going to connect, the user name, the associated password, and the port that we are going to use to make the connection. Once you are ready, click on “Quick Connection” and the process will start.
Even though FileZilla is the most popular option, it is not the only one. Another FTP client for Windows is called WinSCP, and it can be downloaded free of charge and allows you to use FTP, SFTP, FTPS, SCP, S3 or WebDAV protocols. It also allows you to set restrictions, create rules and automate processes.
Another one you can use is called SmartFTP. It allows us to connect to FTP servers but also allows us to connect to cloud storage systems if you want to access Google Drive, Yandex Disk, etc. It can be downloaded for free.
What is the default port?
The default port used by FTP is TCP 21 for control and port 20 for the data channel. Port 21 is the one used for control and from it the connection would be managed but no data is transferred. There are different modes available to perform the file transfer, active or passive. In the active mode, TCP port 20 is the one on which the data channel is created while on the client a random port is chosen which is always higher than TCP 1024. On the other hand, there is a passive mode in which control port 21 is used to choose the external port to connect to, the client establishes a connection from the port indicated. The latter is the most commonly used and the former poses some security problems, as it implies that all ports greater than 1024 are open. For this reason, the second is usually the most popular mode.
FTP security risks
Should you use the FTP protocol for file exchange? They can have some risks that we must take into account. As explained by the company Panda Security, the FTP protocol presents many vulnerabilities. Why? It is easy to access old FTP servers with common user names such as FTP or Anonymous without needing a password.
How to avoid risks when using the FTP?
If you want to protect your FTP server you should follow a series of basic tips such as having a secure access password. You should also disable the guest user option if you want to improve security. Another recommended tip to take into account is to change the default port.