Friday, March 28, 2008

Diagnosing Problems With Custom Domains - Case Study #1

Google Custom Domains, that give us the possibility of having a blog with a non-Blog*Spot address, are a major improvement over plain old Blog*Spot to many bloggers. Occasionally though, problems arise, and diagnosing the symptoms, to allow us to focus on the problems, will require some technical ability, and the right tools. And, note the possible effects of cache and DNS latency, any time that you diagnose or examine a custom domain problem.

Here's a baseline study, which will show what you should see as the best possible case. My first custom domain, "martinezumc.org", I was able to setup with 2 "CNAME" referrals. I call this "symmetrically configured".

There are 4 URLs to study here.

First, let's dig the DNS records for the primary domain "martinezumc.org".
;; QUESTION SECTION:
;martinezumc.org. IN A

;; ANSWER SECTION:
martinezumc.org. 3600 IN CNAME ghs.google.com.
ghs.google.com. 61848 IN CNAME ghs.l.google.com.
ghs.l.google.com. 300 IN A 72.14.207.121

Next, the "www" alias "www.martinezumc.org".
;; QUESTION SECTION:
;www.martinezumc.org. IN A

;; ANSWER SECTION:
www.martinezumc.org. 3600 IN CNAME ghs.google.com.
ghs.google.com. 61733 IN CNAME ghs.l.google.com.
ghs.l.google.com. 185 IN A 72.14.207.121

This shows us two "CNAME" referrals in operation, ie "symmetrically configured".
martinezumc.org. 3600 IN CNAME ghs.google.com.
www.martinezumc.org. 3600 IN CNAME ghs.google.com.


Now, let's look at browser connect logs. First, this is what we get for the primary domain "martinezumc.org".
3/28/2008 07:42:11 Trying http://martinezumc.org
Header:
HTTP/1.0 200 OK
Content-Type: text/html; charset=UTF-8

Next, the "www" alias "www.martinezumc.org".
3/28/2008 07:35:25 Trying http://www.martinezumc.org
Redirect!
Header:
HTTP/1.0 302 Moved Temporarily
Location: http://martinezumc.org
Content-Type: text/html; charset=UTF-8

The key item here is
HTTP/1.0 302 Moved Temporarily
Location: http://martinezumc.org

When I setup the domain, the blog "martinezumc.blogspot.com" was published to "martinezumc.org", and I selected "Redirect www.martinezumc.org to martinezumc.org.".

Now, let's look at the BlogSpot URLs.
3/28/2008 07:52:38 Trying http://martinezumc.blogspot.com
Redirect!
Header:
HTTP/1.0 301 Moved Permanently
Location: http://martinezumc.org/
Content-Type: text/html; charset=UTF-8

and
3/28/2008 07:53:33 Trying http://www.martinezumc.blogspot.com
Redirect!
Header:
HTTP/1.0 301 Moved Permanently
Location: http://martinezumc.org/
Content-Type: text/html; charset=UTF-8

Both "martinezumc.blogspot.com" and "www.martinezumc.blogspot.com" redirect to "martinezumc.org". Blogger only recently corrected two design deficiencies in the Custom Domains product
  • Allowed "www.martinezumc.blogspot.com" to redirect to "martinezumc.org".
  • Allowed me to make the selection "Redirect www.martinezumc.org to martinezumc.org."
When these corrections were made, the Custom Domain product became usable for people with serious domain publishing requirements. This lets all 4 possible URLs (enumerated above) work predictably.

The domain "martinezumc.org" isn't typical of all Custom Domain setups, unfortunately. Next, I'll show an asymmetrically configured domain, my recently setup "nitecruzr.net".

>> Top

2 comments:

juan2thepaab said...

Thank you for this tutorial.

So suppose I want my blog to live at "domain.com" -- no www. Is it correct to create a C NAME entry for "domain.com" that points to ghs.google.com?

This looks weird because the other cname entries are simple, like "www" instead of "www.domain.com".

know what i mean?

(I'm using GoDaddy)

Thanks!

Chuck said...

If you can setup a pair of "CNAME" referrals, you can make either the primary domain ("domain.com") or the "www" alias ("www.domain.com") as the primary URL ("make the blog to live") - your choice. If not, you use Google Apps for the primary domain.