Azure – Geo-blocking in Azure

Did you see this page about Creating geo.conf From MaxMind GeoIP Country Database? It's linked from the bottom of the nginx Geo Module you mentioned.

You will have to divide the countries up into categories (Western, Asian, African audience etc.) yourself but that shouldn't be too difficult.

If it were me doing this, I would do it in the app using one of the APIs that MaxMind provide with the actual data or pushing the data from the CSV file into my database. Don't forget that there are functions available to convert IP addresses from dotted-quad to numerical formats and back (ip2long(), INET_NTOA(), etc.) so you don't have to use the sample code given there.

Ultimately you might be a little bit screwed here - you have to deal with Microsoft licensing to do what you want legally (you can stick your head in the sand and ignore the licensing considerations too -- many companies do that - but to keep it kosher you need to get the client licenses).
The licensing issues are between you and Microsoft (we don't do that here).

From a technical standpoint what you're proposing seems sound, though I would also suggest you consider this configuration:

• Install QuickBooks on some server you can reliably back up; Store the QuickBooks DB there.
  (I'm not a fan of Azure/Snapshots for backups by the by - you want real, reliable backups that you have control over in case Azure goes away and you need to recover to a physical box in your office...)

• Install QuickBooks client software on the users' workstations.
  This avoids the remote desktop licensing, but it means you need to keep all the workstations up to date.

Another option to consider to avoid the server issues entirely is QuickBooks Enterprise Hosting Solutions - basically this is "QuickBooks Online for the Enterprise customer" & equivalent to what joeqwerty suggested but I believe you get all the Enterprise features/functionality (you'd have to check that with your Intuit rep though).