PHP check IP and useragent

<?php

$guest_ip = $_SERVER['REMOTE_ADDR'];
$guest_agent = $_SERVER['HTTP_USER_AGENT'];
$ip_list = file('ip.txt');
$agent_list = file('agent.txt');
$success = false;


 foreach($agent_list as $agent_num)
    foreach ($ip_list as $ip_num)
        if($agent_num == $guest_agent)
            if($ip_num == $guest_ip)
                {
                    $success = true;
                     break;
                }


if($success == true)
nextgo();
else
drop();


function nextgo()
{
    echo "congulation!";
}
function drop()
{
    echo "false";
}

?>