tnftpd is a port of the NetBSD FTP server to other systems. It offers many enhancements over the traditional BSD ftpd, including per-class configuration directives via ftpd.conf(5), RFC 2389 and draft-ietf-ftpext-mlst-11 support, IPv6, transfer rate throttling, and more. tnftpd was formerly known as lukemftpd, and earlier versions are present in Mac OS X 10.2 (as ftpd) and FreeBSD 5.0 (as lukemftpd).
FSP is a UDP-based protocol for transferring files. It has many benefits over FTP, mainly for running anonymous archives. It is usable on lines with high packet loss ratio (70% WiFi), can go behind firewalls and unnoticed by port scans (because of UDP), does not overload networks when hosting ISOs or movies, share files on modem lines without eating all of the bandwidth, and keeps lamers away from your site (they don't know how to get to it). This project is active continuation of the FSP code base (abandoned 1996-2003).
Beeweeb Internet File Server Workgroup for Windows is a secure and fast alternative to complex and expensive VPN solutions. It enables users connecting from the Internet to access, backup, and share files stored on any file server, just as you would do within a LAN. The BWB protocol includes SSL encryption and allows direct access to files, avoiding time-consuming downloading and uploading procedures. It is easy to install and configure. Users log on to the server by means of the Beeweeb's thin free client (Beeweeb Mapper) with just an address (i.e. username@servername) and a password. It is scalable to serve up to thousands of users, and it is a perfect solution for ISPs and hosting providers who wish to offer innovative online storage, backup, and file-sharing services.
linux-ftdp-ssl is the netkit ftp server with encryption support. ftpd-ssl replaces normal ftpd using SSL authentication and encryption. It operates together with normal ftp. It checks if the other side is also talking SSL, if not it falls back to normal ftp protocol. Advantages over normal ftp(d) are that your passwords and the data you send will not go in cleartext over the line, and nobody can get it with tcpdump or similar tools.
ftp-ssl is similar to the standard FTP client and it interoperates with normal ftpd, but it uses SSL authentication and encryption. It checks if the other side is also talking SSL, and if not it falls back to the normal FTP protocol. Advantages over normal FTP include encryption of passwords and transmitted data, preventing network sniffers from acquiring secret information (most notably passwords).