NSLOOKUP query
Hi all,
When I do an NSLOOKUP on google.com, I get three IP addresses as below
Non-authoritative answer:
Name: google.com
Addresses: 64.233.167.99, 64.233.187.99, 72.14.207.99
When I do an NSLOOKUP on www.google.com, I get this:
Non-authoritative answer:
Name: www.l.google.com
Addresses: 64.233.167.104, 64.233.167.147, 64.233.167.99
Aliases: www.google.com
Firstly, why are there three addresses linked to "google.com"?
Why is one IP address shared between www.google.com and google.com?
Is it something to do with CNAME entries in the DNS?
When I do an NSLOOKUP on google.com, I get three IP addresses as below
Non-authoritative answer:
Name: google.com
Addresses: 64.233.167.99, 64.233.187.99, 72.14.207.99
When I do an NSLOOKUP on www.google.com, I get this:
Non-authoritative answer:
Name: www.l.google.com
Addresses: 64.233.167.104, 64.233.167.147, 64.233.167.99
Aliases: www.google.com
Firstly, why are there three addresses linked to "google.com"?
Why is one IP address shared between www.google.com and google.com?
Is it something to do with CNAME entries in the DNS?
Comments
The following 3 dns servers contain the google.com authoritative google.com dns zones:
64.233.167.99, 64.233.187.99, 72.14.207.99
The following 3 servers contain web server software such as IIS, Apache, or something else that hosts Google's web pages for public use:
64.233.167.104, 64.233.167.147, 64.233.167.99
In this case: 64.233.167.99 is both a dns server and a web server. For the google.com dns zone, there is an NS record for 64.233.167.99 and an A record that points www to 64.233.167.99.
Glad I could clear that up for you. You can believe that there are definitely more than 3 web servers also for Google. Basically, what they do, is have 3 server farms (data centers). Each of those ip addresses are actually the ip address for 3 separate Network Load Balance Clusters. This ensures additional redundancy.
http://www.baselinemag.com/print_article2/0,1217,a=182560,00.asp
Found that with, what else, a google search.
That is incredible! That's a massive amount of hardware. Imagine landing the contract to supply servers for Google.
"Oh, we'll just need another 10000 servers, thanks"
I think they would probably agree to your quote as well if you could gurantee a quick installation haha
People have a hard time thinking of one name let alone 45,000!