FTP is a protocol which allows you to transfer data from one computer to another over a network or the internet. It is the common protocol used by many web hosts to allow their clients to upload their website content to their servers. FTP uses 2 pieces of software to work. The first is an FTP server which is installed on the receiving computer (typically on a web server) and the second is the client version which is used to upload to the computer running the FTP server software. A good side of FTP is that it is a protocol which many operating systems support. This allows a computer running Windows to transfer to a server running a version of Linux.
What else can FTP do?
FTP is also capable of downloading files and renaming files with some versions also able to change file permissions if the FTP server permits it such as on a Linux web server.
FTP Security
FTP is not a secure protocol because it sends usernames and passwords in clear text. Packet sniffers can be used to intercept the FTP session and find the username and password. However, if you mix FTP with SSL then the contents of the FTP session are not sent clear text.
FTP Problems
Being in the hosting industry for a few years I have seen a number of problems when clients try FTP their files to the web servers. One of these is the ports that are needed to be opened in order to establish communication and transmit the data. Depending on what mode you choose will depend on what firewall tweaks you need to make. Typically ports 20 and 21 are needed to be opened for Active mode transfers.
Although FTP is an old protocol with some vulnerabilities, it still is an excellent way of transferring files to and from a web server.
