You use File eXchange Protocol (FXP) when you connect to two servers and transfer files between them. FXP lets you copy files from one FTP-server to another. CuteFTP Pro supports this protocol.
When you transfer files between two remote hosts using an FXP client, the maximum transfer speed does not depend on your connection but only on the connection between the two hosts, which is usually much faster than your own connection. Because it is a direct connection you will not be able to see the progress or the transfer speed of the files.
Although FXPing is very easy, there are a few restrictions to transferring the files. Both hosts have to support PASV mode and must allow PORT commands to foreign hosts. The FXP client tells the destination FTP server to listen for a connection by sending a "PASV" command. The source FTP server then connects to the data port reported by the destination server (after a successful PASV command). All the data then goes directly from the source to the destination server and both servers only report fail/success messages to the FTP client.
At least one of the two remote hosts has to be a non-NT FTP-server, like a UNIX host or anything else. You can move files from a non-NT FTP-server to a NT FTP-server and the other way around, but you CANNOT FXP from one NT server to another NT server.