Update virtual-networks.md

Adding info on how to use conditional forwarders
Adding info on the IP address of Azure DNS that should be used

Author: AhmadAbdullah91

articles/ai-services/agents/how-to/virtual-networks.md

@@ -154,7 +154,7 @@ For Agents, private endpoints ensure secure, internal-only connectivity for the
 | **Azure Cosmos DB**        | Sql          | `privatelink.documents.azure.com` | `documents.azure.com` |
 | **Azure Storage**          | blob         | `privatelink.blob.core.windows.net` | `blob.core.windows.net` |
 
-
+To create a conditional forwarder in the DNS Server to the Azure DNS Virtual Server. Use the list of zones mentioned in the above table. The Azure DNS Virtual Server IP address is 168.63.129.16.
 
 ### Access your secured agents
 
@@ -180,4 +180,4 @@ Our goal is to accelerate the development and deployment of AI agents without co
 
 
 ## What's next?
-You’ve now successfully configured a Network Secure Account and project, use the [quickstart](../quickstart.md) to create your first agent. 
+You’ve now successfully configured a Network Secure Account and project, use the [quickstart](../quickstart.md) to create your first agent.