Extract Google IP CIDRs

cidr.php

<?php
$blocks = [];
$result = shell_exec("nslookup -q=TXT _spf.google.com 8.8.8.8");
preg_match_all("%include:(.+?) %", $result, $matches, PREG_SET_ORDER);

foreach($matches as $block) {
    $blocks[] = $block[1];
}

print_r($blocks);

$ips = [];
foreach($blocks as $block) {
    $result = shell_exec("nslookup -q=TXT $block 8.8.8.8");
    preg_match_all("%ip4:(.+?) %", $result, $matches, PREG_SET_ORDER);
    foreach($matches as $match) {
        $ips[] = $match[1];
    }
}

foreach($ips as $ip) {
    echo "set_real_ip_from $ip;\n";
}