FTP (File Transfer Protocol) is a network protocol used to transfer files between a client and a server on a computer network. FTP is one of the oldest protocols in use and was designed to allow efficient data transfer over the Internet and local networks.
FTP works on a client-server model, where the client initiates a connection to the FTP server to download or upload files. Authentication is usually required via a username and password, although it is also possible to access FTP servers anonymously if they are configured that way.
Additionally, FTP has two main modes of operation:
- Active mode: the server establishes the return connection to the client to transfer data.
- Passive mode: the client requests that the server listen on a specific port for data transfer, which is useful for clients behind firewalls.
Although FTP is effective for basic file transfer, it is not the most secure method, as user credentials and transferred data are not encrypted by default. For this reason, many organizations have migrated to more secure protocols such as FTPS (FTP Secure), which adds an SSL/TLS security layer, or SFTP (SSH File Transfer Protocol), which uses SSH to encrypt all transfer traffic.