Aftpd is an FTP server for anonymous access designed for Unix-like operating systems. It uses an asynchronous model of connection processing and provides service for all users within a single process; can use multiple threads to run more efficiently on multi-core systems, with each thread serving multiple clients simultaneously; uses effective mechanisms of transferring files, minimizing copying of data in RAM (sendfile or a combination of the system calls mmap/writev); uses effective event notification schemes (kqueue on FreeBSD and epoll on Linux); uses poll or select in older systems; and supports IPv6. For safety, it works as an unprivileged user and uses chroot.