从“gethostbyaddr”字符串中提取主机名

Question

I wish to extract the exact hostname from an ip address but what i am receiving is an entire string of the address.

I would just like to extract only the Host Name from the the string. Can any one point me in the right direction ?

Here is the snippet of the code being used:-

<?php

    $ip = $_SERVER['REMOTE_ADDR'];
    $fullhost = gethostbyname(gethostbyaddr($ip));
    $host = preg_replace("/^[^.]+./", "*.", $fullhost);
?>

Host: <?=$host?>

The output received from it is :-

Host: *.36.64.182.airtelbroadband.in

I would just like to display Airtel Broadband and nothing else to the user

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Answer 1

You can try this:

$host      = gethostbyaddr($_SERVER['REMOTE_ADDR']); // gets the full hostname
$hostNames = explode(".", $host);      // explodes into parts divided by DOT
echo $hostNames[count($hostNames)-2]; // take what you need
// $hostNames[count($hostNames)-1];   -> in
// $hostNames[count($hostNames)-2];   -> airtelbroadband

You might also want to look into geoip.
This is a basic PHP extension that can be installed using PECL.

string geoip_isp_by_name ( string $hostname )
The geoip_isp_by_name() function will return the name of the Internet Service Provider (ISP) that an IP is assigned to.

This function is currently only available to users who have bought a commercial GeoIP ISP Edition. A warning will be issued if the proper database cannot be located.