Why do FTP clients lock-up or time-out when listing directories or downloading files from my FTP server?
Your BBS computer is probably behind a Network Address Translator (NAT). NAT functionality is typically built into router/firewall devices. If your NAT device supports active and passive FTP servers “behind” the NAT, then you should have no problems. Unfortunately, this is not always the case: some cheaper consumer-level firewalls do not handle FTP server connections correctly or they do not support FTP servers listening on non-standard ports. Sometimes passive (PASV) transfers work fine, but active (PORT) transfers do not, or vice versa. This document contains the technical details about how and why and the recommended solutions. Note: Most web browsers (e.g. Microsoft Internet Explorer) use passive FTP transfer mode by default. Note: Some FTP clients (e.g. the Windows command-line FTP client) only support active mode transfers. Enabling the logging of FTP data channel activity can help diagnose these kinds of problems. This can be done by adding the DEBUG_DATA option to the Options v
