Private connectivity between Azure SQL Servers for external table link

Senthilnathan Jegadeeswaran 21 Reputation points


I have a question on the network traffic between two Azure SQL DB servers connected to network via private endpoint.

The setup is as below in Azure.

  • A private VNet with two subnets - one for VMs and another one for data services.
  • Two SQL database servers for two different projects. DB Server B should connect to DB Server A to retrieve some common data to reuse. This is done
    using external table approach. i.e. DB Server B has external tables linked to DB Server A's tables.
  • Private endpoint between DB Server A to Data Subnet and DB Server B to Data Subnet and the setup is identical.
  • Both SQL Server firewalls allow "Public Access" but "Allow all azure IP" disabled due to security reasons.


When I queried the external table from database inside Server B, it throws an error that the IP address of server B is not allowed to access database in Server A. The IP address that it shows in the error seems to be a public IP and belongs to Azure DC of the resource's said location.

I can make it work by allowing this public IP of Server B in Server A's firewall but it's not allowed in our security policy to whitelist a public IP of Azure DC. If it's a public IP of our org, then it's allowed.

Any idea how can I establish a private connection between these two SQL servers to make external tables work using this setup?

Azure SQL Database
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Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
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Azure Private Link
Azure Private Link
An Azure service that provides private connectivity from a virtual network to Azure platform as a service, customer-owned, or Microsoft partner services.
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  1. msrini-MSFT 9,256 Reputation points Microsoft Employee


    You can use Private Endpoint to access SQL from VNET resources. SQL to SQL over Private Endpoint is not supported as of today. You can raise a feature request here:

    For this scenario, if you know the outbound IP of your SQL, you can whitelist the IP. If that is not available , you will need to allow Azure IPs.

    Karthik Srinivas