Frox is a transparent FTP proxy that runs under Linux and *BSD. It should also work on other UNIX OSes that use ipfilter.
Frox Features:
* active - passive mode conversion for data connections.
* It supports caching of FTP downloads, either through a local cache, or by redirecting connections through another proxy such as squid.
* Downloads may be transparently scanned for viruses (through an external scanner).
* Optional non-transparent proxy support by logging in with user@host:port.
* Options to bind to a specific interface, chroot, and drop priveleges for security.
* Written with security in mind, default setup runs as a non-root user in a chroot jail.
Continue Reading... Frox Features:
* active - passive mode conversion for data connections.
* It supports caching of FTP downloads, either through a local cache, or by redirecting connections through another proxy such as squid.
* Downloads may be transparently scanned for viruses (through an external scanner).
* Optional non-transparent proxy support by logging in with user@host:port.
* Options to bind to a specific interface, chroot, and drop priveleges for security.
* Written with security in mind, default setup runs as a non-root user in a chroot jail.
source:http://linuxpoison.blogspot.com/2011/02/135781677510379.html