SOCKS4 proxy server sometimes rejects FTP data connection?

The FTP Extended Passive Mode (EPSV) continues to be both a solution to problems AND the cause of problems. The Chilkat FTP2 component will automatically use EPSV (as opposed to PASV) if it detects the FTP server supports EPSV. This is generally a good thing to do, and often solves problems. However, occasionally it can be the cause of problems. […]