Configure DNS server policies

This page describes how to configure DNS server policies and use them with Virtual Private Cloud (VPC) networks. Before you use this page, review the DNS server policies overview.

Before you begin

The Cloud DNS API requires that you create a Google Cloud project and enable the Cloud DNS API.

If you are creating an application that uses the REST API, you must also create an OAuth 2.0 client ID.

1. If you don't already have one, sign up for a Google Account.
2. Enable the Cloud DNS API in the Google Cloud console. You can choose an existing Compute Engine or App Engine project, or you can create a new project.
3. If you need to make requests to the REST API, you need to create an OAuth 2.0 ID. See Setting up OAuth 2.0.
4. In the project, note the following information that you need to input in later steps:
   • The client ID (xxxxxx.apps.googleusercontent.com).
   • The project ID that you want to use. You can find the ID at the top of the Overview page in the Google Cloud console. You can also ask your user to provide the project name that they want to use in your app.

If you have not run the Google Cloud CLI previously, you must run the following command to specify the project name and authenticate with the Google Cloud console:

gcloud auth login

To choose a different project than one you have chosen previously, specify the --project option at the command line.

Permissions required for this task

To perform this task, you must have been granted the following permissions or the following IAM roles.

Permissions

• dns.policies.create to create a DNS server policy
• dns.policies.delete to delete a DNS server policy
• dns.policies.get to fetch the current configuration of a DNS server policy
• dns.policies.list to list all DNS server policies associated with a project
• dns.policies.update to update a DNS server policy
• dns.managedZones.list to list managed zones

Roles

• DNS Administrator (roles/dns.admin)

Create DNS server policies

Each DNS server policy object can define any of the following server policies:

• An inbound DNS server policy, enabling inbound forwarding
• An outbound DNS server policy, specifying one or more alternative name servers
• Both an inbound and an outbound DNS server policy
• A DNS64 server policy

Each VPC network can reference no more than one DNS server policy. If you need to define both inbound and outbound forwarding for a VPC network, create one policy that defines both an inbound and an outbound policy. You can't configure DNS64 with an inbound DNS server policy.

Create an inbound DNS server policy

To create an inbound DNS server policy, follow these instructions. Cloud DNS creates a set of inbound forwarder IP addresses from the primary IPv4 address ranges of subnets in each VPC network to which the policy applies. After you create your policy, you can list the entry points that Cloud DNS creates.

Important: For important details about how inbound server entry points associate DNS queries with a VPC network and region, carefully review the Inbound server policies section of the Cloud DNS server policies page.

Console

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click Create policy.

3. In the Name field, enter the name of the inbound DNS server policy that you want to create, such as inbound-dns-server-policy.

4. In the Inbound query forwarding section, select On.

5. You can optionally enable DNS64 to enable communication between IPv6-only workloads and IPv4-only destinations. See Configure DNS64 for more information.

6. You can optionally enable private DNS logs in the Logs section, however, this can increase your costs in Cloud Logging.

7. In the Networks list, select VPC networks that you want to bind to this DNS server policy.

   A network can only be bound to a single policy. If you can't select a network from the list, it's being used by another policy. To see what network is being used by a policy, view the In use by column on the DNS server policies page.

8. Click Create.

gcloud

To create an inbound DNS server policy, run the dns policies create command:

gcloud dns policies create NAME \
    --description="DESCRIPTION" \
    --networks="VPC_NETWORK_LIST" \
    --enable-inbound-forwarding

Replace the following:

• NAME: a name for the policy
• DESCRIPTION: a description for the policy
• VPC_NETWORK_LIST: a comma-delimited list of VPC networks that the DNS server policy must bind to

Terraform

resource "google_dns_policy" "default" {
  name                      = "example-inbound-policy"
  enable_inbound_forwarding = true

  networks {
    network_url = google_compute_network.default.id
  }
}

resource "google_compute_network" "default" {
  name                    = "network"
  auto_create_subnetworks = false
}

Create an outbound DNS server policy

To specify a list of alternative name servers for a VPC network, you can create an outbound DNS server policy.

Important: For important details about how use of alternative name servers affects VPC network-scoped response policies, VPC network-scoped private zones, and Compute Engine internal DNS, carefully review the Outbound server policies section of the "DNS server policies overview" page. Also review Alternative name server types, routing methods, and addresses and Alternative name server network requirements.

Console

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click Create policy.

3. In the Name field, enter the name of the outbound DNS server policy that you want to create, such as outbound-dns-server-policy.

4. In the Inbound query forwarding section, select Off.

5. You can optionally enable private DNS logs in the Logs section, however, this can increase your costs in Cloud Logging.

6. In the Alternative DNS servers (Optional) section, click Add item, and enter the IP address of your outbound DNS servers in the IP Address field.

   • Select the Private forwarding checkbox if you want to force private routing to outbound DNS servers.

7. In the Networks list, select VPC networks that you want to bind to this DNS server policy.

8. Click Create.

gcloud

To create an outbound DNS server policy, run the dns policies create command:

gcloud dns policies create NAME \
    --description="DESCRIPTION" \
    --networks="VPC_NETWORK_LIST" \
    --alternative-name-servers="ALTERNATIVE_NAMESERVER_LIST" \
    --private-alternative-name-servers="PRIVATE_ALTERNATIVE_NAMESERVER_LIST"

Replace the following:

• NAME: a name for the policy
• DESCRIPTION: a description for the policy
• VPC_NETWORK_LIST: a comma-delimited list of VPC networks that query the alternative name servers
• ALTERNATIVE_NAMESERVER_LIST: a comma-delimited list of IP addresses that you can use as alternative name servers
• PRIVATE_ALTERNATIVE_NAMESERVER_LIST: a comma-delimited list of IP addresses that you can use as alternative name servers, accessed by using private routing

Terraform

resource "google_dns_policy" "default" {
  name = "example-outbound-policy"

  alternative_name_server_config {
    target_name_servers {
      ipv4_address    = "172.16.1.10"
      forwarding_path = "private"
    }
    target_name_servers {
      ipv4_address = "172.16.1.20"
    }
  }

  networks {
    network_url = google_compute_network.default.id
  }
}

resource "google_compute_network" "default" {
  name                    = "network"
  auto_create_subnetworks = false
}

Create a DNS server policy for both inbound and outbound forwarding

Console

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click Create policy.

3. In the Name field, enter the name of the inbound DNS server policy that you want to create, such as inbound-outbound-dns-server-policy.

4. In the Inbound query forwarding section, select On.

5. You can optionally enable private DNS logs in the Logs section, however, this can increase your costs in Cloud Logging.

6. In the Alternative DNS servers (Optional) section, click Add item, and enter the IP address of your outbound DNS servers in the IP Address field.

   • Select Private forwarding if you want to force private routing to outbound DNS servers.

7. In the Networks list, select VPC networks that you want to bind to this DNS server policy.

8. Click Create.

gcloud

To create a DNS server policy for both inbound and outbound forwarding, run the dns policies create command:

gcloud dns policies create NAME \
    --description="DESCRIPTION" \
    --networks="VPC_NETWORK_LIST" \
    --alternative-name-servers="ALTERNATIVE_NAMESERVER_LIST" \
    --private-alternative-name-servers="PRIVATE_ALTERNATIVE_NAMESERVER_LIST" \
    --enable-inbound-forwarding

Replace the following:

• NAME: a name for the policy
• DESCRIPTION: a description for the policy
• VPC_NETWORK_LIST: a comma-delimited list of VPC networks where inbound forwarding addresses must be created and that must query the alternative name servers
• ALTERNATIVE_NAMESERVER_LIST: a comma-delimited list of IP addresses that you can use as alternative name servers
• PRIVATE_ALTERNATIVE_NAMESERVER_LIST: a comma-delimited list of IP addresses that you can use as alternative name servers, accessed by using private routing.

Terraform

resource "google_dns_policy" "example_policy" {
  name                      = "example-policy"
  enable_inbound_forwarding = true

  enable_logging = true

  alternative_name_server_config {
    target_name_servers {
      ipv4_address    = "172.16.1.10"
      forwarding_path = "private"
    }
    target_name_servers {
      ipv4_address = "172.16.1.20"
    }
  }

  networks {
    network_url = google_compute_network.network_1.id
  }
  networks {
    network_url = google_compute_network.network_2.id
  }
}

resource "google_compute_network" "network_1" {
  name                    = "network-1"
  auto_create_subnetworks = false
}

resource "google_compute_network" "network_2" {
  name                    = "network-2"
  auto_create_subnetworks = false
}

List inbound forwarder entry points

When an inbound DNS server policy applies to a VPC network, Cloud DNS creates a set of regional internal IP addresses that serve as destinations to which your on-premises systems or name resolvers can send DNS queries. These addresses serve as entry points to the name resolution order of your VPC network.

Note: If you disable and then re-enable inbound forwarding or if you delete and recreate a VPC network, the entry point IP addresses change.

Google Cloud firewall rules do not apply to the regional internal addresses that act as entry points for inbound forwarders. Cloud DNS accepts TCP and UDP traffic on port 53 automatically.

Each inbound forwarder accepts and receives queries from Cloud VPN tunnels or Cloud Interconnect attachments (VLANs) in the same region as the regional internal IP address. VM instances can access the inbound forwarder through any of the internal IP addresses in the same VPC network. To access inbound forwarding, either the network interface must have an external IP address or a subnet of the NIC must have Private Google Access enabled.

Console

View the list of inbound forwarder entry points for a policy:

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click the name of the policy.

3. On the Policy details page, click the In use by tab.

Each network bound to the policy lists the Inbound query forwarding IP addresses.

gcloud

To list the set of regional internal IP addresses that serve as entry points for all inbound forwarding policies, run the compute addresses list command:

gcloud compute addresses list \
    --filter='purpose = "DNS_RESOLVER"' \
    --format='csv(address, region, subnetwork)'

Update DNS policies

The following sections provide information about changing VPC networks and enabling or disabling inbound forwarding.

Change VPC networks

The following list describes what happens when you change the list of VPC networks to which a DNS policy applies:

• If the policy specifies an inbound policy, entry points for inbound forwarders are created in VPC networks as needed.

• If the policy specifies an outbound policy, the name resolution order of each VPC network is updated to include the specified alternative name servers.

Console

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click the name of the policy you want to change.

3. Click Edit policy.

4. In the Networks list, select or clear the checkboxes next to the VPC networks.

5. Click Save.

gcloud

To modify the list of networks to which a DNS server policy applies, run the dns policies update command:

gcloud dns policies update NAME \
    --networks="VPC_NETWORK_LIST"

Replace the following:

• NAME: a name for the policy
• VPC_NETWORK_LIST: a comma-delimited list of VPC networks to which the policy applies; the list of VPC networks that you specify replaces the previous list

Enable or disable inbound forwarding

You can enable inbound forwarding for a DNS server policy that defines only an outbound policy (alternative name server). You can also disable inbound forwarding for an existing DNS policy.

Console

Enable inbound forwarding for a DNS server policy:

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click the name of the policy you want to change.

3. Click Edit policy.

4. In the Inbound query forwarding section, select On.

5. Click Save.

Disable inbound forwarding for a DNS server policy:

1. Open the Cloud DNS server policies page.
2. Click the name of the policy you want to change.
3. Click Edit policy.
4. In the Inbound query forwarding section, select Off.
5. Click Save.

gcloud

To enable inbound forwarding for a DNS server policy, run the dns policies update command:

gcloud dns policies update NAME \
    --enable-inbound-forwarding

To disable inbound forwarding for a DNS server policy, specify the--no-enable-inbound-forwarding flag:

gcloud dns policies update NAME \
    --no-enable-inbound-forwarding

Replace NAME with the name of the policy.

List DNS policies

Console

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Any DNS server policy created in your project is listed.

gcloud

To list DNS server policies in your project, run the dns policies list command:

gcloud dns policies list

Delete a DNS policy

Console

To delete a DNS server policy, it must not be bound to any network. Update your policy to remove all networks before deleting the policy.

1. In the Google Cloud console, open the Cloud DNS server policies page.

   Go to Cloud DNS server policies

2. Click Delete by the name of the policy you want to delete.

gcloud

To delete a DNS server policy, run the dns policies delete command:

gcloud dns policies delete NAME

Replace NAME with the name of the policy to delete.

What's next

• To find solutions for common issues that you might encounter when using Cloud DNS, see Troubleshooting.
• To get an overview of Cloud DNS, see Cloud DNS overview.