$url = "https://www.mbnanetaccess.com/NASApp/NetAccess/Login";

$browser = LWP::UserAgent->new();
$browser->timeout(10);

@fields = [username => 'myusername',
           password => 'mypassword'
           ];

my $response = $browser->post($url,@fields);

if ($response->is_error())
{
    printf "Error!";
    printf "%s\n", $response->status_line;
}
$contents = $response->content();
print $contents;