title: DNS nslookup or dig command and reverse command
body: <p>Type command 'dig google.com' in cmd, then I can get result as following picture.</p>
  
  <pre><code>google.com.                      300    IN  A   74.125.235.104
  
  google.com.                      300    IN  A   74.125.235.110
  
  google.com.                      300    IN  A   74.125.235.98
  
  google.com.                      300    IN  A   74.125.235.99
  
  google.com.                      300    IN  A   74.125.235.103
  
  google.com.                      300    IN  A   74.125.235.96
  
  google.com.                      300    IN  A   74.125.235.100
  
  google.com.                      300    IN  A   74.125.235.101
  
  google.com.                      300    IN  A   74.125.235.102
  
  google.com.                      300    IN  A   74.125.235.97
  
  google.com.                      300    IN  A   74.125.235.105
  </code></pre>
  
  <p>Type reverse command like 'dig '74.125.235.104'(first IP address of results) then I can get result following picture. </p>
  
  <pre><code>        104.235.125.74.in-addr.arpa.     9174   IN  PTR nrt19s02-in-f8.1e100.net.
  </code></pre>
  
  <p>And another reverse command like 'dig '74.125.235.103' (not in the results but near the results), then I can result as following.</p>
  
  <pre><code>      103.235.125.74.in-addr.arpa.     19820    IN  PTR nrt19s02-in-f7.1e100.net.
  </code></pre>
  
  <p>'nrt19s02-in-f8.1e100.net' is one of domain name that google has. But it looks like a encrypted message.</p>
  
  <p>It may be There are some rules, but i can't find them except increasing and decreasing number.</p>
  
  <p>What are nrt or kix mean?</p>
  
  <p>If you enter 'nrt19s02-in-f8.1e100.net' in Internet explorer, you can reach google main page. It supposed to be a redirecting.</p>
  
  <p>Those are my thought and my questions are following.</p>
  
  <p><strong>1. Rule or meaning of thoes domain name(kix, nrt....etc.)</strong></p>
  
  <p><strong>2. Purpose or advantage of operating domains like above. Yahoo or Facebook also manages like that.</strong> </p>
  
  <p><strong>3. Do you know any method that collecting all IP addresses of 'google.com'?</strong></p>
  
  <p>p.s I did this experiment using nslookup and captured results, but i couldn't upload image file becuase my reputation is low. So i did same experiments using dig command. DNS server is 8.8.8.8(Google public DNS)</p>
  
  <p>Any ideas you have are welcome!</p>