$filename = 'file.zip'; # for example
use LWP::UserAgent;
use HTTP::Request::Common;
my $url = "http://www.domain.com/$filename";
my $ua = new LWP::UserAgent(keep_alive=>1);
$ua->credentials('www.domain.com:80', '', 'user', 'pass');
$request = GET $url;
$response = $ua->request($request);
print "response:" . $response->code . "\n";

##</code><code>##

$ua->credentials('www.domain.com:80', '', 'user'=>'pass');