FTP
File Transfer Protocol
The original specification for the File Transfer Protocol was written by Abhay Bhushan and published as RFC 114 on 16 April 1971.
http://en.wikipedia.org/wiki/File_Transfer_Protocol
Protocol, Active vs Passive
http://slacksite.com/other/ftp.html
A quick summary of the pros and cons of active vs. passive FTP is also in order: Active FTP is beneficial to the FTP server admin, but detrimental to the client side admin. The FTP server attempts to make connections to random high ports on the client, which would almost certainly be blocked by a firewall on the client side. Passive FTP is beneficial to the client, but detrimental to the FTP server admin. The client will make both connections to the server, but one of them will be to a random high port, which would almost certainly be blocked by a firewall on the server side.