As reported in Mandrake's bug tracker bug 12285

(http://qa.mandrakesoft.com/show_bug.cgi?id=12285), when connecting to an
IPv6 host with FTP, --disable-epsv (or --disable-eprt) effectively disables
the ability to transfer a file. Now, when connected to an FTP server with
IPv6, these FTP commands can't be disabled even if asked to with the
available libcurl options.