Microsoft Certified: DevOps Engineer ExpertDevelop a security and compliance planHard

A DevOps team is developing a new serverless application using Azure Functions. The application needs to connect to an on-premises database securely, without exposing the Azure Function to the public internet or requiring complex network configurations. The on-premises network has a site-to-site VPN connection to an Azure Virtual Network (VNet). Which Azure Functions networking feature should be enabled to allow secure, private access to the on-premises database?

  1. AAzure Front Door with Web Application Firewall (WAF)
  2. BHybrid Connections for Azure Function
  3. CPrivate Endpoint connection to Azure Function
  4. DVNet Integration for Azure Function
Show answer & explanation

Correct answer: D. VNet Integration for Azure Function

Azure Functions VNet Integration allows your function app to access resources within your VNet, including resources reachable through VNet gateways (like a VPN Gateway connecting to an on-premises network). This enables secure, private access to the on-premises database without exposing the function to the public internet.

Why the other options are wrong

  • A. Azure Front Door with WAF protects *inbound* traffic to web applications and does not facilitate outbound connectivity from an Azure Function to an on-premises database.
  • B. Hybrid Connections provide a secure, simplified way to connect to on-premises resources, but VNet Integration is generally preferred and more robust for complex VNet scenarios with VPNs, offering full VNet capabilities.
  • C. Private Endpoint provides *inbound* private access to the Azure Function, but the requirement is for *outbound* access from the Function to an on-premises resource.

Azure Functions VNet Integration

A networking feature that allows an Azure Function app to access resources within an Azure Virtual Network and resources reachable through that VNet, including on-premises networks via VPN/ExpressRoute.

  • Enables outbound traffic from the Function into the VNet.
  • Does not provide inbound access to the Function from the VNet.
  • Simplifies secure connectivity to private resources without public internet exposure.

Memory trick: Integrate your Function into the VNet, and it can 'see' On-Prem!

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