Whether you’re downloading a movie from a website or uploading your latest production to a cloud server, file transfer is all around us. Yet, ensuring secure FTP transmissions can be tricky without a managed file transfer solution like IBM Aspera.
FTP is a client-server communications protocol that requires a login to send or receive files. Secure FTP servers like SFTP enable encrypted connections to protect data.
FTP
FTP is a client-server protocol that offers a means to transfer computer files from one host on a network to another. It is used to publish websites, transfer images and backups and for many other purposes. It uses a control connection on port 21 to communicate with the server and a data channel on any dynamically allocated ports for file transfers. It is a stateful protocol that requires user authentication to establish and maintain a session.
FTP was designed in the 1970s by Abhay Bhushan to allow computers in a network to access and use files as though they were local files on the host computer. It along with telnet were the first formal network applications that allowed indirect access to hosts and was an important precursor to what would become the Internet.
There are several variations of FTP. Most commonly used are FTP over SSL (FTPS) or FTPS with TLS (FTPSES). Both of these protocols provide secure connections between the host and the remote computer.
Unlike HTTP, which drops and re-establishes its TCP connection after each request, FTP sessions are generally established and held open for multiple transfers. This allows for a more efficient use of network resources than establishing a new connection each time an individual transfer is required.
The FTP protocol supports three modes of data transmission, ASCII, binary and continuous. The default mode is ASCII, which is most compatible with the original FTP implementations on microcomputer systems. Binary and continuous modes were introduced to support users of mainframes and minicomputers that used different word sizes from 8 bits, such as 9-bit for DEC PDP-10 systems.
Authentication is accomplished using a clear-text sign-in protocol that requires a username and password. However, the server can be configured to allow anonymous FTP access. For secure transmission that encrypts both the username and password and encrypts the contents of the transferred files, an alternative to FTP is SSH file transfer protocol (SFTP).
What are some free FTP clients?
There are a number of free and open source FTP clients available for Windows, macOS and Linux. These include FileZilla, WinSCP and CoffeeCup Free FTP. They offer features like a dual-pane interface for easy file transfer, remote text editing and directory synchronization.
For those that prefer to use a proprietary software application, there are a number of commercial FTP clients available for business and home users. These applications offer more advanced features, such as scripting capabilities and a more customizable and user-friendly interface. Many of these also support SFTP and FTPS protocols.
