On the FTP > Advanced tab you can specify hosts and networks that can skip the transparent mode of the FTPFile Transfer Protocol proxy. Additionally, you can define which FTP servers are allowed to be accessed.
FTP Proxy Skiplist
Hosts and networks (FTP clients as well as FTP servers) listed here are excluded from the transparent interception of FTP traffic. However, to allow FTP traffic for these hosts and networks, select the Allow FTP traffic for listed hosts/nets checkbox. If you do not select this checkbox, you must define specific firewall rules for the hosts and networks listed here.
Note – The FTP proxy is unable to communicate with FTP servers that use Active Directory authentication. To enable FTP clients to connect to an FTP server of that kind, add the server to the FTP proxy skiplist.
Select or add FTP servers or networks that are allowed to be accessed from your hosts/networks. You can create exceptions for some FTP clients or FTP servers to bypass this list on the Exceptions tab.