Bernstein, D. J. "PASV Security and PORT Security." Online article at http://cr.yp.to/ftp/security.html.
http://cr.yp.to/publicfile.html. (15 April 2002) (The home of publicfile, D. J. Bernstein's secure FTP/HTTP server. Like djbdns, it uses Bernstein's daemontools and ucspi-tcp packages.)
Carnegie Mellon University (CERT Coordination Center). "Anonymous FTP Abuses." Online article at http://www.cert.org/tech_tips/anonymous_ftp_abuses.html (15 April 2002).
Carnegie Mellon University (CERT Coordination Center). "Anonymous FTP Configuration Guidelines." Online article at http://www.cert.org/tech_tips/anonymous_ftp_config.html (15 April 2002).
Carnegie Mellon University (CERT Coordination Center). "Problems with the FTP PORT Command or Why You Don't Want Just Any PORT in a Storm." Online article at http://www.cert.org/tech_tips/ftp_port_attacks.html (15 April 2002).
Garfinkel, Simson and Gene Spafford. Practical Unix and Internet Security, Sebastopol, CA: O'Reilly & Associates, 1996.
Klaus, Christopher. "How to Set up a Secure Anonymous FTP Site." Online article; no longer maintained (Last update: 28 April 1994), but available at http://www.eecs.umich.edu/~don/sun/SettingUpSecureFTP.faq.
http://www.proftpd.org. (The official ProFTPD home page.)
http://rsync.samba.org. (The official rsync home page.)