When an external FTP client connects to a Gateway Server (GS),  FTP commands are processed as described below.

1). MLSD command: to look at the list of files available for download. BC presents a list of files. You can do this with FileZilla to see this.

2). GET <fileName>: In this case, the Gateway Server contacts to the Interior Server  (IS) for the information and the IS responds to the GS. GS sends it to the external client.

Note that when BC connects, inbox/outbox folders are the root folder for the FTP client once it connects to the FTP server. Although BC will honor the commands, it will not allow you to create your own directory structure like a "real-classic" FTP server under inbox/outbox folders. You have to use the directory structure provided by BC itself, which consists of the protocol and the operations.