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Type command 'dig google.com' in cmd, then I can get result as following picture.

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

Type reverse command like 'dig '74.125.235.104'(first IP address of results) then I can get result following picture. 

        104.235.125.74.in-addr.arpa.     9174   IN  PTR nrt19s02-in-f8.1e100.net.

And another reverse command like 'dig '74.125.235.103' (not in the results but near the results), then I can result as following.

      103.235.125.74.in-addr.arpa.     19820    IN  PTR nrt19s02-in-f7.1e100.net.

'nrt19s02-in-f8.1e100.net' is one of domain name that google has. But it looks like a encrypted message.

It may be There are some rules, but i can't find them except increasing and decreasing number.

What are nrt or kix mean?

If you enter 'nrt19s02-in-f8.1e100.net' in Internet explorer, you can reach google main page. It supposed to be a redirecting.

Those are my thought and my questions are following.

1. Rule or meaning of thoes domain name(kix, nrt....etc.)

2. Purpose or advantage of operating domains like above. Yahoo or Facebook also manages like that.

3. Do you know any method that collecting all IP addresses of 'google.com'?

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)

Any ideas you have are welcome!

Jehyun Shim
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1 Answers1

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  1. I have look at this myself today. First code (left most three letters) appears to be geographic location information. kix and nrt are both IATA airport codes in Japan. They also have major data centres, with possible Google colo. In Australia, for example, I get starting with syd. There is also colo in Sydney used by Google. It seems that other companies also use IATA codes. It seems useful since datacentres are mostly in major population centres that usually have airports with IATA codes.

  2. Is, supposedly, so that Google (or whoever) can direct you to a local server to improve performance and potentially save money (since internal crossconnects in data centres can be used to connect direct to your ISP). But also allows customisation based on GeoIP, and possibly makes tracking and ad targeting easier for Google. The exact records returned depend on the DNS server queried rather than on your own IP, it seems. It looks to be possible to query DNS server in another country and get a different result.

  3. I believe that Google's IP address spaces are: 64.233.160.0 - 64.233.191.255 66.102.0.0 - 66.102.15.255 66.249.64.0 - 66.249.95.255 72.14.192.0 - 72.14.255.255 74.125.0.0 - 74.125.255.255 209.85.128.0 - 209.85.255.255 216.239.32.0 - 216.239.63.255 I don't know which are used by google.com. I do know that here I am getting 74.125.237.x addresses for google.com, and 74.125.31.x for www.google.com, and 74.125.237.x for mail.google.com. I suspect that there is overlap, and that single IPs are used for multiple google 'services'. Also, Google public DNS of 8.8.8.8 is different servers depending on location, so results will vary depending on where in the world you are.

user45742
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