Azure Firewall should have DNS Proxy enabled

Medium Azure General firewall-azure-firewall-dns-proxy

Applies to

Microsoft.Network/azureFirewalls

What CGPulse checks

A resource passes this rule when dnsProxy must equal true. Anything else is reported as a finding with the evaluated property value attached as evidence.

How to fix it

Enable DNS Proxy for correct FQDN-based network rule resolution. In Azure Portal: Firewall > DNS settings > enable DNS proxy. See: https://learn.microsoft.com/en-us/azure/firewall/dns-settings

CLI

az network firewall update --ids "{id}" --dns-proxy true

Terraform

resource "azurerm_firewall" "{name}" {
  name                = "{name}"
  resource_group_name = "{rg}"
  location            = var.location
  sku_name            = "AZFW_VNet"
  sku_tier            = "Standard"
  dns_proxy_enabled   = true
  ip_configuration {
    name                 = "fw-ipconfig"
    subnet_id            = "<firewall-subnet-id>"
    public_ip_address_id = "<public-ip-id>"
  }
}

Compliance frameworks

Cloud Security BaselineNS-6

Vendor documentation

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