Configuring FTP Voyager for a Specific Port Range - KB Article #1369Related Articles --
When FTP Voyager uses SSL, NAT routers and proxy servers are sometimes unable to translate these FTP commands because the data is encrypted. When this occurs, FTP Voyager can appear to be "hung" waiting for a LISTing or waiting for a file transfer. In most cases, the use of PASV mode fixes the problem because the FTP server is told to listen for FTP Voyager to connect back to it instead. But when the FTP server is behind a NAT router and improperly configured, PASV mode may be entirely unavailable.
To address this problem, FTP Voyager allows an external IP address and port range to be specified when issuing the PORT command. This option is available under View | Options | Connection | Port Range / Public IP.
Because of the way FTP connections work, a fairly broad port range will be required to accommodate the server. It can take several minutes before the server is allowed to cycle back to the beginning of the port range and reuse ports.
In addition to configuring FTP Voyager, the router or proxy server may need to be configured to map incoming connections on the specified port range to the FTP Voyager computer. Information on configuring routers can be found in this article.