date and add back preview notice

Author: vhorne

articles/dns/private-dns-overview.md

@@ -5,13 +5,18 @@ services: dns
 author: vhorne
 ms.service: dns
 ms.topic: overview
-ms.date: 6/15/2019
+ms.date: 6/12/2019
 ms.author: victorh
 #Customer intent: As an administrator, I want to evaluate Azure Private DNS so I can determine if I want to use it instead of my current DNS service.
 ---
 
 # What is Azure Private DNS?
 
+> [!IMPORTANT]
+> Azure Private DNS is currently in public preview.
+> This preview version is provided without a service level agreement, and it's not recommended for production workloads. Certain features might not be supported or might have constrained capabilities.
+> For more information, see [Supplemental Terms of Use for Microsoft Azure Previews](https://azure.microsoft.com/support/legal/preview-supplemental-terms/).
+
 The Domain Name System, or DNS, is responsible for translating (or resolving) a service name to its IP address.  Azure DNS is a hosting service for DNS domains, providing name resolution using the Microsoft Azure infrastructure. In addition to supporting internet-facing DNS domains, Azure DNS also supports private DNS zones.
 
 Azure Private DNS provides a reliable, secure DNS service to manage and resolve domain names in a virtual network without the need to add a custom DNS solution. By using private DNS zones, you can use your own custom domain names rather than the Azure-provided names available today. Using custom domain names helps you to tailor your virtual network architecture to best suit your organization's needs. It provides name resolution for virtual machines (VMs) within a virtual network and between virtual networks. Additionally, you can configure zones names with a split-horizon view, which allows a private and a public DNS zone to share the name.