FTP or file transfer protocol is used to transfer files between two computers: one is FTP host or server and another is FTP client. In addition to transferring files, FTP helps to gain access to the physical location of the server to modify files such as file deleting, folder creating or even modifying file contents.
Before knowing the difference between active and passive FTP, you need to know how FTP functions. Normally, when you open FTP connectivity with a FTP server, there opens two connections between the computers: one is used to transfer data and another one is used to transfer control signals. Both the channels are TCP connections. For commands, TCP port number 21 is used and the port number 20 is used for data.
Benefit of active FTP: it increase FTP server security
Benefit of passive FTP: it requires less configuration changes on client computer.