Get the internet host name or ISP corresponding to a given IP address.
Most people know how to find and display a visitor's IP address. A visitor's ISP can also be found and displayed much like a visitor's IP address.
Code:
------------------------------------------------------------------------
<?php
$hostname = gethostbyaddr($_SERVER['REMOTE_ADDR']);
echo $hostname;
?>
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In action:
18-97-9-169.crawl.commoncrawl.org