use Net::FTP;
use strict;

my $f = Net::FTP->new(
    Host => "cs.ucl.ac.uk",
    Firewall => "webproxy.local",
    FirewallType => 1,
    Passive => 1,
);

$f->login( "anonymous", "myemail\@mycompany.com" )
    or die( "Failed to log in to FTP server: " . $f->message );

my @list = $f->ls( '/rfc' );
foreach my $fname ( @list ) {
    my $size = $f->size( '/rfc/' . $fname );
    defined( $size )
        or die( "  Failed to get size: " . $f->message );

    print( "  Size of $fname is $size\n" );
}

$f->quit();