If you want to make

Managed File Transfer

available to external clients over the internet, it is important that you only open certain port numbers to the machine in which

Managed File Transfer

is installed.  This can be controlled through your firewall settings.  The firewall settings will depend on whether if the

Managed File Transfer

software is installed in your DMZ (Demilitarized Zone) or the Private (internal) network, and whether if it is used in conjunction with

Managed File Transfer

Gateway.