# What Is FTP and How Does It Work?

FTP (File Transfer Protocol) is a protocol for copying files to remote sites. Due to the fact, that it was born in the early years of the internet, no encryption was implemented. To remedy the situation, [FTPS](https://dotroll.com/en/knowledge-base/books/ftp/page/what-is-ftps-and-how-does-it-work "FTPS") was invented.

FTP has two modes of operation: active and passive. Active means, that the server connects back to the client to transfer data. This is only possible, if the client is not behind a firewall / NAT router. Most home / company sites are protected by such devices, so use of passive mode is recommended.

Below are some third-party clients, without the need for completeness

#### WINDOWS

- [Total Commander](https://dotroll.com/en/knowledge-base/books/ftp/page/how-to-use-ftp-with-total-commander)
- [WinSCP](https://dotroll.com/en/knowledge-base/books/ftp/page/how-to-use-ftp-with-winscp)
- [Filezilla](https://admin.dotroll.com/knowledgebase/98/using-ftp-with-filezilla.html?swcfpc=1)
- [FireFTP](https://dotroll.com/en/knowledge-base/books/ftp/page/how-to-set-up-the-filezilla-ftp-client)
- Cyberduck
- CrossFTP
- FlashFXP
- CuteFTP

#### MAC OS X

- Yummy
- [Filezilla](https://dotroll.com/en/knowledge-base/books/ftp/page/how-to-set-up-the-filezilla-ftp-client)
- FireFTP
- Cyberduck
- CrossFTP
- Fetch
- Transmit
- Captain FTP

#### UNIX/LINUX

- Konqueror KDE
- FTP Natutilus (GMONE)
- Filezilla
- CrossFTP
- gFTP
- FtpCube
- FireFTP
- Midnight Commander

You can find a comparison of FTP clients [here](https://en.wikipedia.org/wiki/Comparison_of_FTP_client_software).

#### SEE MORE

- FTPS
- Illegal PORT command