I want to assign a custom domain name to my Azure blob storage account. In the custom domain setup page it says:

You can map a custom subdomain name to your Blob service endpoint. Windows Azure must verify that you are authorized to modify DNS records for the domain. To verify authorization, create a CNAME resource record with your DNS provider that points from [subdomain].yourdomain.com to justanotherxiodec11.blob.core.windows.net or asverify.[subdomain].yourdomain.com to asverify.justanotherxiodec11.blob.core.windows.net.

However, justanotherxiodec11.blob.core.windows.net doesn't resolve at all. Am I missing something? (Note: I expected to see *mystorageaccountname*.blob.core.windows.net, not justanotherxiodec11... I have no idea what justanotherxiodec11 is.)

ps Unrelated - are the IP addresses that are associated with the mystorageaccountname.blob.core.windows.net host names static or dynamic?

1 Answer 1


It doesn't need to resolve to anything. Microsoft will check your domain's DNS for that record. If it exists, you've proved you at least have control of the domain's DNS records, and as such have proven enough control of the domain for Microsoft's comfort level.

No one other than Microsoft's "does Howiecamp own example.com?" automated system will ever do anything with that subdomain.

  • Wow, totally great point- I am embarrassed I missed that! But then given that the address they have me point to doesn't resolve, what do I ultimately point my custom domain name to once they verify me?
    – Howiecamp
    Sep 21, 2015 at 20:26
  • @Howiecamp They'll give you a different record for that. This one's only for verification.
    – ceejayoz
    Sep 21, 2015 at 21:00
  • Interesting-I just tried this from old portal and got result I expected: "To verify auth, create CNAME record...that points from [subdomain].yourdomain.com to hcblobstorage.blob.core.windows.net." hcblobstorage... is my actual storage account name and it's resolvable (by defn). I think something was broken w/ the new portal bc in my experience w/ Azure custom domains they've always had me create a cname to a resolvable address, in particular mystorageaccount.blob.core.windows.net. Regardless I totally agree w/ your point about DNS though-the address doesn't need to be valid to be verified.
    – Howiecamp
    Sep 21, 2015 at 21:09

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