FTP
BNCs are also often used for FTP, again to either hide the user and server from each other and to route traffic through a specific location. FTP bouncers can be divided into two different categories, entry and traffic.
Entry bouncer acts as a gateway to the server, but it does not hide the existence of the actual server. Entry bouncers, like cubnc can be used in multi-server setup for easy access to each server and load balancing. This removes the need to select which FTP server to login to, when trying to access the server farm.
Traffic bouncers relay traffic through the host they are installed on, and when used, it appears as the bouncer is actually the FTP server thus hiding the real location of the server completely. Multiple traffic bouncers can be installed parallel, in order to balance traffic load across different links. Most elaborate bouncers can even bounce secure SSL/TLS connections.
Read more about this topic: BNC (software)