transfer will run on any system connected to the Internet that has Perl 5 with the Net:FTP module installed. The remote system must be running an FTP server that can respond to the FTP requests. Also, the remote system must be connected to the Internet before starting the transfer.
Either host can be running any operating system that can satisfy these requirements. This means that either host can be a Windows box or a Macintosh with the appropriate software. Perl is freely available for either and free FTP servers are also available on the Internet.