oftpd is designed to be as secure as an anonymous FTP server can possibly be. It runs as non-root for most of the time, and uses the Unix chroot() command to hide most of the systems directories from external users - they cannot change into them even if the server is totally compromised! It contains its own directory change code, so that it can run efficiently as a threaded server, and its own directory listing code (most FTP servers execute the system "ls" command to list files).