What is The File Transfer Protocol (FTP)
The File Transfer Protocol (FTP) is both a TCP/IP protocol and software that permits the transferring of files between computer systems. Because FTP has been implemented on numerous types of computer systems, files can be transferred between disparate systems (for example, a personal computer and a minicomputer). It uses ports 20 and 21 by default.
FTP sessions work in passive or active modes. In active mode, after a client initiates a session via a command channel request, the server initiates a data connection back to the client and begins transferring data. In passive mode, the server instead uses the command channel to send the client the information it needs to open a data channel. Because passive mode has the client initiating all connections, it works well across firewalls and Network Address Translation (NAT) gateways.
FTP can be configured to allow or deny access to specific IP addresses and can be configured to work with exceptions.
Users can work with FTP via a simple command line interface (for example, from a console or terminal window in Microsoft Windows, Apple OS X or Linux ) or with a dedicated graphical user interface (GUI). Web browsers can also serve as FTP clients. Although the protocol can be run within most browsers, a number of FTP applications are available; FileZilla is one of the most popular.
FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS). SSH File Transfer Protocol (SFTP) is sometimes also used instead, but is technologically different.
FTP sessions work in passive or active modes. In active mode, after a client initiates a session via a command channel request, the server initiates a data connection back to the client and begins transferring data. In passive mode, the server instead uses the command channel to send the client the information it needs to open a data channel. Because passive mode has the client initiating all connections, it works well across firewalls and Network Address Translation (NAT) gateways.
FTP can be configured to allow or deny access to specific IP addresses and can be configured to work with exceptions.
Users can work with FTP via a simple command line interface (for example, from a console or terminal window in Microsoft Windows, Apple OS X or Linux ) or with a dedicated graphical user interface (GUI). Web browsers can also serve as FTP clients. Although the protocol can be run within most browsers, a number of FTP applications are available; FileZilla is one of the most popular.
FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS). SSH File Transfer Protocol (SFTP) is sometimes also used instead, but is technologically different.