use HTTP::WebTest;
my $webtest=new HTTP::WebTest;
$url="http://mail.rediff.com/";
$proxy="http://192.168.1.60:3128";
@proxy=("proxies",[http=>$proxy]);

$webtest->run_tests(
    [
    {
                test_name=>"Posting the data for logging into site..",
                url      => $url."cgi-bin/login.cgi/",
                method   => POST,
                params=>[
                           FormName=>existing,
                           login=>'username',
                           passwd=>'********'
                        ],
    }
    ],
    {
    @proxy,
    }
);

$a=$webtest->current_response->content;