Is it possible to use an external table with an Azure SQL VM?

Question

Is it possible to use an external table with an Azure SQL VM?

John Ellison 1

Hello,

I am using an instance of SQL Server on an Azure VM, and I wanted to know if it is possible to use ADX External Tables. The VM does not have a public IP.

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Answer 1

Smaran Thoomu 32,520 Microsoft External Staff Moderator

Hi John Ellison

Yes, you can use Azure Data Explorer (ADX) external tables to query data from a SQL Server running on an Azure VM, but there are a few things to check:

The SQL VM must be reachable from ADX - if there’s no public IP, make sure the VM is in the same virtual network (VNet) as your ADX cluster or that there’s VNet peering between them.

You’ll need to create a data connection in ADX using the externaldata() function or by defining an external table that connects via ODBC or SQL connector.

Ensure the SQL port (default 1433) is open in the VM’s NSG (Network Security Group) so ADX can connect.

If the SQL VM isn’t network-accessible (no public or private route), ADX won’t be able to read from it.

Reference:

Azure SQL external table connection strings

Hope this helps. Do let us know if you any further queries.

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John Ellison 1 Reputation point

2025-10-22T14:59:15.1333333+00:00

If ADX no longer supports VNET impersonation, how could I achieve VNET peering between ADX and the VM? Would that require a private endpoint?
Smaran Thoomu 32,520 Reputation points Microsoft External Staff Moderator

2025-10-22T16:51:36.3533333+00:00
John Ellison If VNet impersonation isn’t supported, you can still achieve secure network connectivity between your Azure Data Explorer (ADX) cluster and your SQL Server VM by using one of the following options:

VNet Peering – If both the ADX cluster and the SQL VM are deployed in different VNets (within the same or different subscriptions), you can configure VNet peering between them.

This allows private IP-based communication without exposing the VM publicly.

Ensure that the SQL port (1433) is allowed through the VM’s NSG and that “Allow VNet traffic” is enabled.

Private Endpoint – Alternatively, you can create a Private Endpoint for ADX.

This maps ADX to a private IP address within your VNet, enabling secure access to resources (like the SQL VM) over Azure’s private network.

This option is ideal if you need tighter security and compliance control.

If your ADX cluster is managed private (in VNet-injected mode), then peering or private endpoints are the only supported approaches for connectivity to private resources like your SQL VM.

Hope this clarifies!

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Is it possible to use an external table with an Azure SQL VM?

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