vsftpd is a GPL licensed FTP server for UNIX systems, including Linux. It is secure and extremely fast. It is stable. Don't take my word for it, though. Below, we will see evidence supporting all three assertions. We will also see a list of a few important sites which are happily using vsftpd. This demonstrates vsftpd is a mature and trusted solution.vsftpd is an FTP server, or daemon. The "vs" stands for Very Secure.