Sunday, September 13, 2009

Your Blog, Custom Domains, And The Quadruplet Google Apps Servers

Some people can't see the forest, for the trees. Occasionally, we see a query from a perplexed blog owner, seeking to publish to a custom domain.
Google wants us to repeat the same IP address 4 times?
216.239.32.21
216.239.34.21
216.239.36.21
216.239.38.21
Uh, aren't they're the same? Why the needless duplication?

Like quadruplets (newly born human children), you may need name tags to distinguish one server from the other. But, if you look closely enough, no, they aren't the same. As always, I'll present these examples using excerpted Dig logs.
mydomain.com. 3600 IN A 216.239.32.21
mydomain.com. 3600 IN A 216.239.34.21
mydomain.com. 3600 IN A 216.239.36.21
mydomain.com. 3600 IN A 216.239.38.21
www.mydomain.com. 3600 IN CNAME ghs.google.com.

"ghs.google.com" is a DNS server array, with multiple levels and multiple redundant parts. We use "ghs.google.com" to resolve the "www" alias of the domains, using "CNAME" referral. Most custom domains are published to the "www" alias - so "ghs.google.com" is massively robust, with redundant parts.

If we use a similar "CNAME" referral to resolve the domain root, aka the "naked domain", we could interfere with resolution of email, FTP, and other possible auxiliary domain services hosted, by the registrar. Instead, we use multiple "A" referrals, mutually redundant.

Long ago, until November 2008, we used "64.233.179.121", "66.249.81.121", and "72.14.207.121", which were triple mutually redundant equivalents of "ghs.google.com". And, you could easily see "64.233.179.121", "66.249.81.121", and "72.14.207.121" as different IP addresses.
mydomain.com. 3600 IN A 64.233.179.121
mydomain.com. 3600 IN A 66.249.81.121
mydomain.com. 3600 IN A 72.14.207.121
www.mydomain.com. 3600 IN CNAME ghs.google.com.

Now, we use the quadruple mutually redundant configuration. And, "216.239.32.21", "216.239.34.21", "216.239.36.21", and "216.239.38.21" are different IP addresses, though they look the same - if you don't look closely enough.
mydomain.com. 3600 IN A 216.239.32.21
mydomain.com. 3600 IN A 216.239.34.21
mydomain.com. 3600 IN A 216.239.36.21
mydomain.com. 3600 IN A 216.239.38.21
www.mydomain.com. 3600 IN CNAME ghs.google.com.

Theoretically, you only need one DNS server - for any domain. Realistically, though, not one server has an unlimited life span - and is 100% reliable.

If your registrar or hosting service does not support 4 x "A" DNS addresses setup, you may want to use a (free) third party DNS host. Now, here's hoping that your registrar allows easy configuration of third party DNS service.

>> Top

11 comments:

Rahul Jadhav said...

Hey i have done as u said for my blog
http://www.smsoholic.com

I have added the following settings
mydomain.com. 3600 IN A 64.233.179.121
mydomain.com. 3600 IN A 66.249.81.121
mydomain.com. 3600 IN A 72.14.207.121
www.mydomain.com. 3600 IN CNAME ghs.google.com.

It was working fine when i entered http://smsoholic.com but suddenly i am getting the
"The requested URL / was not found on this server. " error. Please help

Chuck said...

Rahul,

You need to post this question in BHF: Something Is Broken, immediately. Seriously.

anh3ngơ said...

Hey i have done as u said for my blog
http://www.vnpressnet.com

I have added the following settings
vnpressnet.com. 3840 IN A 64.233.179.121
vnpressnet.com. 3840 IN A 66.249.81.121
vnpressnet.com. 3840 IN A 72.14.207.121
www.vnpressnet.com. 3840 IN CNAME ghs.google.com.

It was working fine when i entered http://vnpressnet.com but when i have added the subdomain http://thuthuat.vnpressnet.com with thuthuat.vnpressnet.com. 3840 IN CNAME ghs.google.com.
i can't access http://vnpressnet.com and cant access http://thuthuat.vnpressnet.com

Chuck said...

Look above, please. Tell me, honestly, which settings do I advise? These?

mydomain.com. 3600 IN A 64.233.179.121
mydomain.com. 3600 IN A 66.249.81.121
mydomain.com. 3600 IN A 72.14.207.121
www.mydomain.com. 3600 IN CNAME ghs.google.com.

Or these?

mydomain.com. 3600 IN A 216.239.32.21
mydomain.com. 3600 IN A 216.239.34.21
mydomain.com. 3600 IN A 216.239.36.21
mydomain.com. 3600 IN A 216.239.38.21
www.mydomain.com. 3600 IN CNAME ghs.google.com.

If you have any confusion or doubts, please be courteous and ask in BHF: How Do I?, or in Nitecruzr Dot Net - Blogging.

Help us to help you.

Muaaz said...

i am using blogspot in pakistan can you send me dns ip setting i will be thankfull to you.
my blogspot address is www.treasureoftutorials.blogspot.com and i want to put my domain www.treasureoftutorials.com
please help me

Chuck said...

Muaaz,

Here's again where I suggest that you post in Blogger Help Forum: How Do I?, for peer support.

A Decorative Life said...

I think the advice being given is confusing people (not deliberately of course) because you do not tell them whether to type in the 3600 IN.

Chuck said...

I think the advice being given is confusing people (not deliberately of course) because you do not tell them whether to type in the 3600 IN.

Everywhere possible, I mention how to read Dig log excerpts. And, I'll ask, over and over, that you please learn to click on the links for more information.

Arjun Chauhan said...

hey when i try to open my blog
its says server not found bt when i try by keeping the blogger tab on
it opens it......

Can u tell me wats the problem... PLZ :(

MY BLOG ADDRESS IS http://www.superstararjunchauhan.info

Chuck said...

Arjun,

This would be a good question for you to ask in BHF: Something Is Broken.

Migi said...

It works, perfect, thank you very much

www.movieguiders.com on godaddy connected to blogspot . (movieguiders.blogspot.com)