The Black Hole MTA is for use in automated package build systems. It looks like a Mail Transfer Agent (MTA) and email goes in but nothing comes out. It is intended for use in chroot jails for automated package build systems.
A secure anonymous FTP server that runs unprivileged for most of the time. This server utilizes a chroot environment and contains its own directory change code, and directory listing code so that it can run efficiently as a threaded server.
Small SMTP wrapper designed to be used in chroot-ed environment as a sendmail command-line tool replacement. e.g. warpper can be used by php ( by function mail ) instead of using SMTP client written in php