We just released a new version of our FTP Monitor Program WatchFTP. If you already own a license, this is a free upgrade. Just install the new version "on top" of your current install.
If you use a secure connection to your FTP site and use Passive mode to connect (the default), you can now enable the new option "Force Host IP". Here the explanation from the WatchFTP help file:
When you use a secure connection all commands and responses between WatchFTP and the FTP server are encrypted. When the FTP server is behind a NAT router, the router can not translate the internal IP addresses (typically 192.168....) to externally accessible IP addresses so they remain unchanged in the FTP response lines to WatchFTP.
When this option is set, WatchFTP will ignore the (unaccessible) IP addresses in the server's responses and always uses the IP address of the FTP server itself.