jftpgw is an FTP proxy/gateway that uses the FTP protocol (unlike those FTP 
proxies that fetch an FTP file but work as an http proxy). You can use it to 
make servers behind a firewall/NAT server (masquerading server) accessible 
or to allow users behind such solutions to transfer files to and from the 
outside of the LAN. With the new sftp support you can also use FTP to get 
files from a machine that is only accessible with an ssh connection (see 
the page on the sftp support).

WWW: http://www.mcknight.de/jftpgw/