Saturday, April 14, 2012

The Simplicity Of A Custom Domain Setup Presents Its Biggest Challenge

Custom domain publishing is a very simple way to give your Blogger blog a non BlogSpot URL - when you follow the recommended procedure. Along with the simplicity, you'll find rather rigid requirements, when any alternative procedure is used.

Too many blog owners, unfamiliar with the complexity of the custom domain infrastructure, try to "fly by the seat of their pants", when they see a requirement that they don't understand. This is the cause of many custom domain publishing problems.

First, understand some of the most common mistakes, made by people who do not use "Buy a domain".
As of 2013/06/23, "Buy a domain" is not offered, as part of "Add a custom domain". That reality does not change any of the necessities of proper domain setup, however. Substituting for "Buy a domain", Blogger offers instructions, in How do I use a custom domain name for my blog?.

To understand the significance of the mistakes that are commonly made, first understand the three basic DNS models, involved in custom domain publishing.
  1. Published To Domain Root - Symmetrical DNS Configuration. The most obvious configuration uses a symmetrical DNS structure - dual "CNAME" referrals.
    mydomain.com. 3600 IN CNAME ghs.google.com.
    www.mydomain.com. 3600 IN CNAME ghs.google.com.
  2. Published To Domain Root - Asymmetrical DNS Configuration, aka "Google Apps". If you have a domain with email, FTP, and other possible auxiliary services, you use an asymmetrical structure, which use Google Apps to let you add auxiliary services, with quadruple DNS server redundancy.
    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.
  3. Published To Non Root Virtual Host. If you wish to add an additional blog to the domain, maybe to add your Blogger blog to your web site, you setup an additional virtual host.
    blog.mydomain.com. 3600 IN CNAME ghs.google.com.
The "Buy a domain" wizard produces an Asymmetrical Configuration. Choice of any one of the three above models determines what URL you may publish the blog.

The published URL is one of the most frequent causes of problems. Do not make any of these mistakes.
  • Only publish to a URL defined by "CNAME" referral to "ghs.google.com".
    The referral target, spelled properly, is essential.
    • Only ghs.google.com
    • Not ghs.l.google.com
    • Not www.ghs.google.com
    • Not ghs.blogger.com
    • Not ghs.blogspot.com
    • Not ghs.gogle.com
    • Not ghs.gooogle.com
    • Not any of a myriad other variations in spelling.
  • Do not publish to a URL defined by "A" referral to the "216.239.nn.21" servers.
  • The "CNAME" referral must target "ghs.google.com", absolutely.
    • Only ghs.google.com
    • Not ghs.google.com.yourdomain.com
    Understand how to define an absolute referral target.
  • The "CNAME" referral must target "ghs.google.com", directly.
    • Only ghs.google.com
    • Not yourdomain.com
    Do not target the domain root, or any other indirect address.
  • Understand how to define a referral host.
  • Only publish to a referral host using lower case letters.

If you use an asymmetrical DNS addressing, target only the four Google servers, as "A" referrals.
216.239.32.21
216.239.34.21
216.239.36.21
216.239.38.21
Use of these four servers is very specific. Do not make these mistakes.

If you use "CNAME" referral for any host, only use one "CNAME" referral - do not add a complementary "A" or "CNAME" address, for that host.
www.mydomain.com. 3600 IN CNAME ghs.google.com.
This is all that is needed.
  • A second "CNAME" referral is not helpful - and is not supported by many registrars.
    www.mydomain.com. 3600 IN CNAME ghs.google.com.
    www.mydomain.com. 3600 IN CNAME ns1.googleghs.com.
    This is not helpful.
  • An additional "A" referral is not helpful - and is not supported by many registrars.
    www.mydomain.com. 3600 IN CNAME ghs.google.com.
    www.mydomain.com. 3600 IN A 64.233.179.121
    This is not helpful.
  • You will, however, need a second "CNAME" for domain ownership verification. You cannot bypass this requirement.

If you must setup the domain yourself, instead of using "Buy a domain", learn the rules - none of them are optional. Follow the rules, and you have a much better chance of having a reliable and working domain - instead of eventually seeing the well known "Another blog ..." or "404 Server Not Found".

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3 comments:

Admin said...

Have 3 additional "A" connections defaults from domain, did I nee to delete them or will work anyway?

Chuck Croll said...

A properly setup domain requires all 4 "A" connections - having "4" is not optional..

http://blogging.nitecruzr.net/2009/09/your-blog-custom-domains-and-quadruplet.html

Ify said...

You the man Chuck! Thanks a lot! You saved me from the asylum! :-) Full story here - http://www.blog.fizzycal.com/2014/08/blogger-vs-dns-management-and-asylum.html