PHP different ips' same proxy check takes too long - php

Question

I read the post here
Test if port open and forwarded using PHP
about how to scan ports of the same proxy . But my problem is I want to do scan the same port of different ip xxx.xxx.xxx.$i and for loop i try to run it from 0 to 255 . I use the same script in the above mentioned post using for loop . But it takes too long to get the answer (actually I dont get any) . Here is the code
for($i=0;$i<2;$i++){
$host = 'xxx.xxx.xxx.'.$i;
$connection = #fsockopen($host, 3128);
if (is_resource($connection))
{
echo '<h2>' . $host . ':' . $port . ' ' . '(' . getservbyport($port, 'tcp') . ') is open.</h2>' . "\n";
fclose($connection);
}
else
{
echo '<h2>' . $host . ':' . $port . ' is not responding.</h2>' . "\n";
}
}