REM Start the ftp
C:\> ftp
REM Connect to the server
ftp> open releases.mozilla.org
REM When asked for username:
REM username: Anonymous
REM password: your email address
REM then you cd-ls to the right directory or type
ftp> cd pub/mozilla.org/firefox/releases/latest/win32/en-US
REM there you'll find the latest version
REM type ls to see the full name of the .exe file
ftp> ls
REM switch to binary mode
ftp> binary
REM start the download
ftp> get "Firefox Setup 13.0.1.exe"
REM Wait for the download and you are done