NSLOOKUP query

plettnerplettner Senior MemberMember Posts: 197
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?

Comments

  • royalroyal New Member Member Posts: 3,352 ■■■■□□□□□□
    google.com will be the server that is hosting the google.com dns. It is google's authoritative servers and there are more than one for redundancy. www.google.com of course is the server that is hosting the web pages. Again, there are more than one web servers that are hosting Google's web pages for redundancy.

    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.
    “For success, attitude is equally as important as ability.” - Harry F. Banks
  • plettnerplettner Senior Member Member Posts: 197
    Thanks. That's cleared it up. I thought it may be to do with reduncancy but I didn't undertsand why www.google.com would have three entires. It's clear now.
  • royalroyal New Member Member Posts: 3,352 ■■■■□□□□□□
    plettner wrote:
    Thanks. That's cleared it up. I thought it may be to do with reduncancy but I didn't undertsand why www.google.com would have three entires. It's clear now.

    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.
    “For success, attitude is equally as important as ability.” - Harry F. Banks
  • sprkymrksprkymrk mikej412's caddy Member Posts: 4,884 ■■■□□□□□□□
    http://dondodge.typepad.com/the_next_big_thing/2006/06/google_data_cen.html
    Today even the closest Google watchers have lost precise count of how big the system is. The best guess is that Google now has more than 450,000 servers spread over at least 25 locations around the world.

    http://www.baselinemag.com/print_article2/0,1217,a=182560,00.asp
    Google runs on hundreds of thousands of servers—by one estimate, in excess of 450,000—racked up in thousands of clusters in dozens of data centers around the world. It has data centers in Dublin, Ireland; in Virginia; and in California, where it just acquired the million-square-foot headquarters it had been leasing. It recently opened a new center in Atlanta, and is currently building two football-field-sized centers in The Dalles, Ore.

    Found that with, what else, a google search. icon_cool.gif
    All things are possible, only believe.
  • plettnerplettner Senior Member Member Posts: 197
    sprkymrk wrote:
    Google runs on hundreds of thousands of servers—by one estimate, in excess of 450,000—racked up in thousands of clusters in dozens of data centers around the world. It has data centers in Dublin, Ireland; in Virginia; and in California, where it just acquired the million-square-foot headquarters it had been leasing. It recently opened a new center in Atlanta, and is currently building two football-field-sized centers in The Dalles, Ore.

    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" icon_lol.gif
  • PashPash Senior Member Member Posts: 1,600 ■■■■■□□□□□
    plettner wrote:
    sprkymrk wrote:
    Google runs on hundreds of thousands of servers—by one estimate, in excess of 450,000—racked up in thousands of clusters in dozens of data centers around the world. It has data centers in Dublin, Ireland; in Virginia; and in California, where it just acquired the million-square-foot headquarters it had been leasing. It recently opened a new center in Atlanta, and is currently building two football-field-sized centers in The Dalles, Ore.

    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" icon_lol.gif

    I think they would probably agree to your quote as well if you could gurantee a quick installation haha
    DevOps Engineer and Security Champion. https://blog.pash.by - I am trying to find my writing style, so please bear with me.
  • SieSie Running on caffine Member Posts: 1,195
    You know how servers get named things like 'Thor' and 'Zeus' (taken from my college nextwork a few years ago) I guess they dont do this here!!

    People have a hard time thinking of one name let alone 45,000! icon_lol.gif
    Foolproof systems don't take into account the ingenuity of fools
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