FTP is a file transfer protocol that uses the TCP transmission control protocol, which allows bidirectional file transfers in the FTP server-FTP client system. The file transfer protocol is an 8-bit protocol, so no data encoding to 7-bits is required, as is the case with email. The FTP protocol can operate in active mode using port 21 for commands and port 20 for data transmission or, in passive mode using port 21 for commands and port with a number above 1024 for data transmission. The FTP server has the ability to install multiple servers of this type on one router. This server allows anonymous access to its resources, however most often you need to enter your login and password to authorize the connection.