We say that DNS is a "distributed" service, because the data provided to you, by DNS, resides not in one, or two, but millions of servers - all over the Internet, and owned by many different companies and individuals.
When you setup a new domain, using a DNS Management utility provided by your domain registrar or another DNS host, you can add the DNS entry when convenient to you. Some DNS management utilities will provide advice
Please wait 12 to 24 hours before trying to use your new URL.or a similar message, simply because the DNS information that you enter, through the utility to your DNS server, has to be distributed to the other DNS servers, all over the Internet.
If your registrar's DNS servers aren't immediately accessible to the Google servers, and you try to publish to your brand new personal domain, you may see problems.
Seconds after you setup the new domain with your registrar, the Blogger "Advanced Settings" wizard may not be able to access the DNS entries which you just created. You'll probably see an old friend
Another blog is already hosted at this address.where the wizard is simply saying to you
We don't see that domain pointing to "ghs.google.com".
In an alternative scenario, your registrar may be immediately accessible to the Google servers, you publish your blog to your custom domain, and you're happy. But wait - there's more! One of your readers, on the other side of the world, sees your advertisement
Hey! Checkout my new non-BlogSpot URL for my blog!and checks it out, and gets another old friend
404 Not Foundbecause your reader uses a DNS server that has no immediate access to your registrar.
The latter two scenarios involve you when you manually set up your custom domain - using your registrar's DNS utility, followed by the Blogger "Advanced Settings" wizard. If you use the Blogger "Buy A Domain For Your Blog" utility, you use neither of those wizards.
The latter wizard takes a mere few seconds, when you're properly prepared. That wizard, replacing both the registrar's utility and the Blogger "Advanced Settings" wizard, can't include a 12 to 24 hour delay. So instead of the wizard taking 12 to 24 hours, it does immediately the work of the registrar's setup, and queues up a separate task - the equivalent of the "Advanced Settings" wizard - to run after the (formerly) "12 to 24" hours. To make sure that the "12 to 24" hour period is not too short, Blogger gives you (the DNS system) "72 hours" to catch up.
When you finish the purchase and setup of your new custom domain, go to your dashboard, and click on the "View Blog" link. There, you will likely see an old friend in the making
Your blog is in transition
Unfortunately, as I state above, the observed transition period has been 72 hours, not "12 to 24 hours". During the 72 hours (currently, slightly longer)
- The blog contents will be published, using the new domain URL.
- The BlogSpot URL will continue to load the blog with the BlogSpot URL.
- The custom domain URL "mydomain.com" will load the blog with the domain URL.
- You will, effectively, appear to have 2 separate blog aliases.
- Accessories like Following will issue mysterious error messages.
This gadget is configured incorrectly. Webmaster hint: Please ensure that "Friend Connect Settings - Home URL" matches the URL of this site.
During the transition period, consider carefully the dual personality of the BlogSpot URLs. Remember that the "www" alias of the BlogSpot URL does not simply redirect to the root of the BlogSpot URL, in the same way that the root of the custom domain URL might redirect to the "www" alias. Expect unpredicted behaviour here, when comparing the BlogSpot URLs.
If you are concerned with search engine reputation and visibility, and are diligently keeping your blog's sitemaps updated, you'll want to consider these issues carefully. You should wait until after the transition period has ended, to update the sitemap.
- You don't want the search engines trying to index a URL that might give them a "404" from their own DNS servers not having your new domain.
- You don't want the search engines trying to index the new URL while the old one is still active, and distinct, lest both the BlogSpot and domain URLs be perceived as "duplicate content".
- You don't want the search engines to start indexing the domain URL, until the BlogSpot URL provides the "301 Moved Permanently" to the domain URL, and gives the new domain its starting kick.
- You do want the search engines to start, re indexing the entire blog, as soon as possible - after migration completes.
If you purchased the domain using "Buy a domain", the above details are not a problem, because Blogger applies the Transition time period, automatically. If you setup the domain yourself, after purchasing from a registrar - as is the case for every domain purchased after 2012 - you need to maintain a Transition period, yourself, or expect problems, during the first week or so.