(PHP 4, PHP 5)
gethostbyname — Get the IPv4 address corresponding to a given Internet host name
Returns the IPv4 address of the Internet host specified by hostname.
The host name.
Returns the IPv4 address or a string containing the unmodified hostname on failure.
Example #1 A simple gethostbyname() example
<?php
$ip = gethostbyname('www.example.com');
echo $ip;
?>