Google Custom Domain - The DNS Referral

Of all of the instructions in the process of setting up a Google Custom Domain for your Blogger blog, none seems to generate so much confusion as setting up the DNS Referral. The instruction itself is so simple,

Add a "CNAME" record. Point "www.yourdomain.com" to "ghs.google.com". And leave the "NS" records to be maintained by your DNS provider.

(Note): This post has been migrated to The Real Blogger Status: The Google Custom Domain Setup - The DNS Referral.

But why a "CNAME" record? And why "ghs.google.com"?

• The host "ghs.google.com" is a load balancing server array. When the reader's DNS client asks for the address of "ghs.google.com", it gets the address of whatever server is available right now.
• In order for you to refer DNS traffic for "yourdomain.com" to "ghs.google.com", rather than to "64.233.179.121" (among many possibilities), you have to use a "CNAME" record. An Address ("A") record will only point to an IP address; to point to a host name you must use a Canonical Name ("CNAME") record.

When a reader of your blog points his browser in your direction, he is referred to "ghs.google.com".

The host "ghs.google.com" then provides a specific IP address, pointing to the single server that will be used to serve your blog to this reader. Another reader for your blog will be accessing it thru a different IP address, using another server. This is called "load balancing". If one readers accesses your blog thru server "D", another reader may access it thru server "F", and a third thru server "G". If server "B" is down, "ghs.google.com" won't offer it for referral. Other readers of other blogs may be using servers "A", "C", and "E" at the same time.

Google provides a load balancing server array, to give your readers the best possible experience. Use the array, not a single server, nor a URL referral. Or prepare for complaints

Gee, your blog performance sucks.

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