Default installed ftp client on windows

You can authenticate with Internet Explorer by including the credentials in the URL, however it will prompt for username and password if you don't enter them.

ftp://username:[email protected]/path/to/files

I haven't tried it but I would expect a non-standard port to be specified in the usual way

ftp://username:[email protected]:10021/path/to/files

You can specify a port on the command line like this

C:\> ftp
ftp> open host.example.com 10021

UPDATE: The Windows explorer address bar usually shows drive letter and path (e.g. C:\somewhere) but you can type in a URL like those above, it can then be used as a drag&drop target for uploading a file to an FTP server.