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The setting: I have a

  • Vnet01

which has 2 subnets:

  • Subnet01 -> here I have mounted the private endpoint of the ADX
  • Subnet02 -> here goes the outbound traffic of the Logic App (the vnet is detached)

Now I want to speak (kql query) in the Logic App to the ADX via the private endpoint, but I get a 500 Internal Error error with the message:

"Message": "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond."

What is interesting about that is that I placed a third subnet Subnet03 in the Vnet01 and added a VM to it. After that I jumped on that VM an could connect successfully to the ADX via telnet <url> 443. Thi shows DNS and routing is working properly but the connection via Logic App still fails.

Why? Any thoughts about it?

1 Answers1

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Created Azure data explorer cluster and added my subnet to the private endpoint of the ADX like below:

enter image description here

Message: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

The error may occur due to the connection attempt to the ADX via the private endpoint is failed however you will able to connect to the ADX via telnet from a VM in Subnet 3 indicates that DNS and routing are working properly.

Ensure that the outbound traffic from Subnet02 to the ADX private endpoint may be blocked by NSG rules. If any such rules are in effect. Network traffic can be limited by NSG rules based on source and destination IP addresses, ports, and protocols.

enter image description here

Make sure in logic app add vnet integration and enabled Route All it will route all outbound traffic from logic app through this specific vnet and allow us to direct our traffic to the same vnet where private endpoint has been deployed.

enter image description here

Setup a Private DNS Zone. Make that the required Private DNS Zone is configured and connected to the VNet so that the private endpoint's DNS resolution functions as desired. The Logic App won't be able to access the private endpoint if DNS resolution isn't done correctly.

enter image description here

  • Check the user-defined routes that are affecting the traffic flow in the virtual network (VNet) or subnet route tables. If any custom routes have been set up, make sure they are not conflicting with the routing required for the Logic App to reach the ADX private endpoint.
  • You can enable diagnostic logs for the Logic App and the ADX service to gather more information about the connection attempts and possible errors. This may provide additional insights into what is causing the issue.

References:

azure-docs/articles/logic-apps/secure-single-tenant-workflow-virtual-network-private-endpoint.md at main · MicrosoftDocs/azure-docs · GitHub

SFTP SSH Connection from Logic App Errors - by Mayank argali

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