Configure private DNS

You can bring your own DNS server(s) to allow name resolution between your private DNS and a HashiCorp Virtual Network (HVN).

All HCP Vault Dedicated tiers support private DNS.

Diagram displaying the DNS resolver on the HashiCorp Cloud Platform HVN
forwarding request to the private DNS resolver

Limitations

Beta feature

Private DNS forwarding is in beta and available for Amazon Web Services (AWS).

During the beta period, private DNS forwarding works with the following limitation:

TLS certificates from a private certificate authority (CA) are not supported

Default limits

Private DNS forwarding has the following default limits:

DNS Forwarding configurations: 1 per HVN
DNS Forwarding rules: 5 per DNS forwarding configuration
Inbound endpoint IPs: 2 per rule

To request higher limits based on your use case, create a support ticket.

Prerequisites

The prerequisites listed are specific to the beta period. Check back at general availability for a list of supported providers and prerequisites.

Access to the HCP Portal
AWS HVN created with a unique address space.
AWS VPC exists and configured with its address space DNS support and DNS hostnames enabled for the VPC to allow DNS lookups of records in the network.
A valid connection between the AWS HVN and the target VPC must exist, using one of the following methods:
- VPC peering connection exists between the target VPC and the HVN, configured with the required routes to enable network traffic between the two networks.
- Transit Gateway Attachment is established between the HVN and the target AWS transit gateway, with valid routes to enable network traffic between the two networks. Note: A valid hvn route specifying the target VPC CIDR must be created in the HVN route table for the Private DNS feature to function properly when using a transit gateway.
Target VPC's private hosted zone is associated with the VPC connected to the HVN via peering or TGW.
Security group exists in the target VPC, which allows inbound traffic on port 53 (both UDP and TCP) from the HVN CIDR block to your self-managed DNS server or AWS Route 53 VPC endpoint.
If using AWS Route 53, ensure an inbound resolver endpoint exists that allows DNS queries from the HVN to be routed to the target VPC endpoint. Select Do53 protocol and choose a Security Group for which you have configured the inbound rules to allow DNS (TCP and UDP) traffic on port 53 from the HVN CIDR block for the resolver endpoint.
HCP service principal user created with a client ID and secret.

Retrieve HCP API token

Request a HCP API token using the HCP API.

Set environment variables for the HCP organization, HCP project, HVN, and peering ID.

$ export HCP_ORG_ID=<HCP_ORG_ID> \
    HCP_PROJ_ID=<HCP_PROJ_ID> \
    HCP_NETWORK_ID=<HCP_NETWORK_ID> \
    PEERING_ID=<PEERING_ID>

Set environment variables for the HCP service principal user HCP_CLIENT_ID and HCP_CLIENT_SECRET:
```
$ export HCP_CLIENT_ID=<HCP_CLIENT_ID> HCP_CLIENT_SECRET=<HCP_CLIENT_SECRET>
```

Retrieve a HCP API token using a HCP service principal user HCP_CLIENT_ID, and HCP_CLIENT_SECRET and store it in the HCP_API_TOKEN variable.

$ HCP_API_TOKEN=$(curl --location "https://auth.idp.hashicorp.com/oauth2/token" \
    --header "Content-Type: application/x-www-form-urlencoded" \
    --data-urlencode "client_id=$HCP_CLIENT_ID" \
    --data-urlencode "client_secret=$HCP_CLIENT_SECRET" \
    --data-urlencode "grant_type=client_credentials" \
    --data-urlencode "audience=https://api.hashicorp.cloud" | jq -r .access_token)

Request a HCP API token using the HCP CLI. These steps assume you configured the HCP CLI using hcp profile init and selected the HCP organization and project where you created the HVN.

Set environment variables for the HCP service principal user HCP_CLIENT_ID and HCP_CLIENT_SECRET.
```
$ export HCP_CLIENT_ID=<HCP_CLIENT_ID> HCP_CLIENT_SECRET=<HCP_CLIENT_SECRET>
```
The HCP service principal client secret is not available after you initially create the secret.

Set environment variables for the HVN, and peering ID.

$ export HCP_NETWORK_ID=<HCP_NETWORK_ID> \
    PEERING_ID=<PEERING_ID>

Authenticate to HCP.
```
$ hcp auth login
```
Complete the browser-based authentication workflow.

Set an environment variable for the HCP organization, and project ID.

$ export HCP_ORG_ID=$(hcp profile display --format json | jq -r .OrganizationID) \
     HCP_PROJ_ID=$(hcp profile display --format json | jq -r .ProjectID)

Retrieve a HCP API token using a HCP CLI and store it in the HCP_API_TOKEN variable.
```
$ HCP_API_TOKEN=$(hcp auth print-access-token)
```

Create DNS forwarding

Note

You can configure private DNS forwarding using the HCP Portal UI or the HCP API. This guide shows the API method.

For a full list of all private DNS forwarding API endpoints, see the HCP API documentation.

Verify you have the required environment variables configured.

$ echo $HCP_API_TOKEN $HCP_ORG_ID $HCP_PROJ_ID $HCP_NETWORK_ID $PEERING_ID

Use the dnsforwardings endpoint to create DNS forwarding. Update highlighted items in the data block with the values for your environment.

Note

The inbound_endpoint_ips is the IP address of your self-managed DNS servers, or the AWS Route 53 VPC endpoint IP addresses.
DNS forwarding ID and rule ID must be unique across your HCP account.
DNS forwarding ID and rule ID cannot exceed 32 characters.
The region must match your HVN's hosted region.
Set connection_type to hvn-peering or tgw-attachment based on your connection type.
Add additional rules after DNS forwarding is in the ACTIVE state.

Choose the appropriate example below based on your connection type:

HVN Peering Connection

Use this example if you connect your HVN to your VPC using HVN peering (connection_type: "hvn-peering").

$ curl --location "https://api.cloud.hashicorp.com/network/2020-09-07/organizations/$HCP_ORG_ID/projects/$HCP_PROJ_ID/networks/$HCP_NETWORK_ID/dnsforwardings" \
  --request POST \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer $HCP_API_TOKEN" \
  --data '{ 
      "dnsForwarding": {
          "id": "dnsforwarding-byod", 
          "peering_id": "your-peering-connection-id", 
          "connection_type": "hvn-peering", 
          "rule": {
              "id": "staging-rule",
              "domain_name": "staging.byod.com",
              "inbound_endpoint_ips": ["10.0.0.12", "10.0.0.9"]
          },
          "hvn": { 
              "location": {
                  "region": {
                      "region": "us-west-2",
                      "provider": "aws"
                  }
              }
          }
      }
  }'

Transit Gateway Attachment

Use this example if you connect your HVN to your VPC using a Transit Gateway (connection_type: "tgw-attachment").

$ curl --location "https://api.cloud.hashicorp.com/network/2020-09-07/organizations/$HCP_ORG_ID/projects/$HCP_PROJ_ID/networks/$HCP_NETWORK_ID/dnsforwardings" \
  --request POST \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer $HCP_API_TOKEN" \
  --data '{ 
      "dnsForwarding": {
          "id": "dnsforwarding-tgw", 
          "peering_id": "your-tgw-attachment-id", 
          "connection_type": "tgw-attachment", 
          "rule": {
              "id": "staging-rule",
              "domain_name": "staging.internal.com",
              "inbound_endpoint_ips": ["10.0.0.12", "10.0.0.9"]
          },
          "hvn": { 
              "location": {
                  "region": {
                      "region": "us-east-1",
                      "provider": "aws"
                  }
              }
          }
      }
  }'

Example output:

{
  "dns_forwarding": {
    "id": "dnsforwarding-byod",
    "hvn": {
      "type": "hashicorp.network.hvn",
      "id": "HCP_NETWORK_ID",
      "uuid": "HCP_NETWORK_ID",
      "location": {
        "organization_id": "HCP_ORG_ID",
        "project_id": "HCP_PROJ_ID",
        "region": {
          "provider": "aws",
          "region": "us-west-2"
        }
      },
      "description": ""
    },
    "state": "CREATING",
    "peering_id": "HCP_NETWORK_PEERING_ID",
    "connection_type": "hvn-peering", 
    "rules": [
      {
        "hvn": {
          "type": "hashicorp.network.hvn",
          "id": "hvn-aws-latest-test-1",
          "uuid": "hvn-aws-latest-test-1",
          "location": {
            "organization_id": "c1597488-1053-4cc8-a536-e84cfef0ea7f",
            "project_id": "b1e20b0d-2411-47e6-adb0-88f39563fbec",
            "region": {
              "provider": "aws",
              "region": "us-west-2"
            }
          },
          "description": ""
        },
        "dns_forwarding_id": "dnsforwarding-byod",
        "state": "CREATING",
        "rule": {
          "id": "staging-rule",
          "domain_name": "staging.byod.com",
          "inbound_endpoint_ips": [
            "10.0.0.12",
            "10.0.0.9"
          ]
        },
        "created_at": "2025-05-14T12:49:52.457815118Z",
        "updated_at": "2025-05-14T12:49:52.457815118Z"
      }
    ],
    "created_at": "2025-05-14T12:49:52.457815118Z",
    "updated_at": "2025-05-14T12:49:52.457815118Z"
  },
  "operation": {
    "id": "OPERATION_ID",
    "state": "PENDING",
    "location": {
      "organization_id": "HCP_ORG_ID",
      "project_id": "HCP_PROJ_ID",
      "region": {
        "provider": "aws",
        "region": "us-west-2"
      }
    },
    "link": {
      "type": "hashicorp.network.dnsforwarding",
      "id": "dnsforwarding-byod",
      "uuid": "dnsforwarding-byod",
      "location": {
        "organization_id": "HCP_ORG_ID",
        "project_id": "HCP_PROJ_ID",
        "region": {
          "provider": "aws",
          "region": "us-west-2"
        }
      },
      "description": "DNS Forwarding (\"dnsforwarding-byod\")"
    },
    "created_at": "2025-05-14T12:49:52.464766Z",
    "updated_at": "2025-05-14T12:49:52.464766Z"
  }
}

You have completed the private DNS forwarding configuration.

Add additional forwarding rules

Note

You can add additional forwarding rules after the initial DNS forwarding configuration is in the ACTIVE state.

To add more forwarding rules for additional domains:

Set the HCP_NETWORK_DNS_FORWARDING_ID environment variable using the DNS forwarding ID from the previous step.
```
$ export HCP_NETWORK_DNS_FORWARDING_ID=<DNS_FORWARDING_ID>
```
Replace <DNS_FORWARDING_ID> with the ID you used when creating the DNS forwarding configuration (e.g., dnsforwarding-byod or dnsforwarding-tgw).

Create the additional forwarding rule.

$ curl --location "https://api.cloud.hashicorp.com/network/2020-09-07/organizations/$HCP_ORG_ID/projects/$HCP_PROJ_ID/networks/$HCP_NETWORK_ID/dnsforwardings/$HCP_NETWORK_DNS_FORWARDING_ID/rules" \
  --request POST \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer $HCP_API_TOKEN" \
  --data '{
      "dnsForwardingRule": {
          "rule": {
              "id": "prod-rule",
              "domain_name": "prod.byod.com",
              "inbound_endpoint_ips": [
                  "10.0.0.13",
                  "10.0.0.14"
              ]
          },
          "hvn": {
              "location": {
                  "region": {
                      "region": "us-west-2",
                      "provider": "aws"
                  }
              }
          }
      }
  }' | jq

Note

The dns_forwarding_id must match the ID of the DNS forwarding configuration created in the previous step (e.g., "dnsforwarding-byod" or "dnsforwarding-tgw").

Example output:

{
  "dns_forwarding_rule": {
    "hvn": {
      "type": "hashicorp.network.hvn",
      "id": "HCP_NETWORK_ID",
      "uuid": "HCP_NETWORK_ID",
      "location": {
        "organization_id": "HCP_ORG_ID",
        "project_id": "HCP_PROJ_ID",
        "region": {
          "provider": "aws",
          "region": "us-west-2"
        }
      },
      "description": ""
    },
    "dns_forwarding_id": "HCP_NETWORK_DNS_FORWARDING_ID",
    "state": "CREATING",
    "rule": {
      "id": "prod-rule",
      "domain_name": "prod.byod.com",
      "inbound_endpoint_ips": [
        "10.0.0.12",
        "10.0.0.11"
      ]
    },
    "created_at": "2025-05-14T13:40:59.044410083Z",
    "updated_at": "2025-05-14T13:40:59.044410143Z"
  },
  "operation": {
    "id": "OPERATION_ID",
    "state": "PENDING",
    "location": {
      "organization_id": "HCP_ORG_ID",
      "project_id": "HCP_PROJ_ID",
      "region": {
        "provider": "aws",
        "region": "us-west-2"
      }
    },
    "link": {
      "type": "hashicorp.network.dnsforwarding.rule",
      "id": "prod-rule",
      "uuid": "prod-rule",
      "location": {
        "organization_id": "HCP_ORG_ID",
        "project_id": "HCP_PROJ_ID",
        "region": {
          "provider": "aws",
          "region": "us-west-2"
        }
      },
      "description": "DNS Forwarding Rule (\"prod-rule\")"
    },
    "created_at": "2025-05-14T13:40:59.053776Z",
    "updated_at": "2025-05-14T13:40:59.053776Z"
  }
}