Microsoft Azure shares many commonalities with Office 365. When you sign up you are given a default .onmicrosoft.com domain but you can also add you own custom domain. here’s how to do just that.

Login to your Windows Azure portal at:
http://manage.windowsazure.com

From the menu on the left locate the Active Directory icon, which is near the bottom and select it.
You should then see a single entry called Default Directory displayed, select this.

From the menu that now appears across the top select DOMAINS. You’ll then see the above message indicating that you can add a custom domain.
Select ADD A CUSTOM DOMAIN.

In the field that appears, enter the custom domain you wish to use and then press the add button at the bottom.

You should now see a message at the top of the dialog saying that the domain has been successfully added.
Select the arrow in the bottom right to move to the next page in the process.

Much like Office 365 you’ll need to verify that you own this domain. You do that be adding a DNS record to your domain records and having Windows Azure verify it.
There are a number of verification options but the best is normally a simple TXT record. If you therefore select RECORD TYPE as TXT record at the top you’ll be provided with the DNS information you need to add to your domain.

You then got to the name records for you domain and add the supplied details to match the record selected in Windows Azure.

When you have updated your domain record return to Windows Azure and select the verify button at the bottom.
Windows Azure will then query the DNS records of your domain to verify that a matching record can be found. If so, you will receive a verification confirmation message at the top of the dialog as shown above.
Press the check mark in the lower right to complete the process.

You should now see the domain you just added listed in the domains option as shown above.
Again, much like Office 365 you can add multiple domains to Windows Azure as required.
With that done, now we can start utilizing this custom domain inside Windows Azure and I’ll cover that in upcoming blog posts.