How Data Snipper from my local is getting connected to Cognitive services which is in Azure though all the outbound port rules are restricted to true using Terraform scrips

Question

I Installed Data snipper locally and try to connect to Cognitive services on Azure Which I created using Private end point and outbound port rules are restricted but still I am able to connect and previously it was not working

Answer 1

Possible Causes and Resolutions

Private Endpoint and Azure Private Link

When you create a private endpoint for Azure Cognitive Services, the traffic to the service remains within the Azure network.

If your local machine is accessing Azure through a VPN or ExpressRoute, the private endpoint can enable access as long as the network configuration aligns.

DNS Configuration

• The DNS resolution for the private endpoint is essential. If your local system is resolving the Cognitive Services endpoint to its private IP (assigned by the private endpoint), traffic will bypass public routes and adhere to the private network.
• Previously, if this was not configured, your connection would fail. Check your DNS setup to confirm.

Firewall Rules and Exceptions

• Outbound port restrictions might not apply to traffic routed through a VPN or a private endpoint.

Steps to verify :

• Use the Azure portal or Azure CLI to review the effective network security rules for the Cognitive Services resource and the private endpoint subnet.
• Run a DNS query (e.g., nslookup <Cognitive Services endpoint>). Ensure it resolves to the private endpoint IP.
• Use tools like Wireshark or Fiddler to capture traffic from your local system and verify the destination IP and ports.
• Inspect the Terraform configuration for:
  • Outbound rule specifics.
  • Private endpoint-related settings.
  • Any overlooked exceptions.

Links to help you :

• Private Endpoint for Azure Cognitive Services
• Manage Outbound Traffic in Azure
• Using Terraform with Azure