Connect privately to API Management using an inbound private endpoint

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You can configure an inbound private endpoint for your API Management instance to allow clients in your private network to securely access the instance over Azure Private Link.

• The private endpoint uses an IP address from an Azure VNet in which it's hosted.

• Network traffic between a client on your private network and API Management traverses over the VNet and a Private Link on the Microsoft backbone network, eliminating exposure from the public internet.

• Configure custom DNS settings or an Azure DNS private zone to map the API Management hostname to the endpoint's private IP address.

With a private endpoint and Private Link, you can:

• Create multiple Private Link connections to an API Management instance.

• Use the private endpoint to send inbound traffic on a secure connection.

• Use policy to distinguish traffic that comes from the private endpoint.

• Limit incoming traffic only to private endpoints, preventing data exfiltration.

Limitations

• Only the API Management instance's Gateway endpoint supports inbound Private Link connections.
• Each API Management instance supports at most 100 Private Link connections.
• Connections aren't supported on the self-hosted gateway or on a workspace gateway.

Prerequisites

• An existing API Management instance. Create one if you haven't already.
  • The API Management instance must be hosted on the stv2 compute platform.
  • Do not deploy (inject) the instance into an external or internal virtual network.
• A virtual network and subnet to host the private endpoint. The subnet may contain other Azure resources.
• (Recommended) A virtual machine in the same or a different subnet in the virtual network, to test the private endpoint.

• Use the Bash environment in Azure Cloud Shell. For more information, see Quickstart for Bash in Azure Cloud Shell.

  

• If you prefer to run CLI reference commands locally, install the Azure CLI. If you're running on Windows or macOS, consider running Azure CLI in a Docker container. For more information, see How to run the Azure CLI in a Docker container.

  • If you're using a local installation, sign in to the Azure CLI by using the az login command. To finish the authentication process, follow the steps displayed in your terminal. For other sign-in options, see Sign in with the Azure CLI.

  • When you're prompted, install the Azure CLI extension on first use. For more information about extensions, see Use extensions with the Azure CLI.

  • Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.

Approval method for private endpoint

Typically, a network administrator creates a private endpoint. Depending on your Azure role-based access control (RBAC) permissions, a private endpoint that you create is either automatically approved to send traffic to the API Management instance, or requires the resource owner to manually approve the connection.

Steps to configure private endpoint

1. Get available private endpoint types in subscription
2. Disable network policies in subnet
3. Create private endpoint - portal
4. List private endpoint connections to the instance
5. Approve pending private endpoint connections
6. Optionally disable public network access

Get available private endpoint types in subscription

Verify that the API Management private endpoint type is available in your subscription and location. In the portal, find this information by going to the Private Link Center. Select Supported resources.

You can also find this information by using the Available Private Endpoint Types - List REST API.

GET https://management.azure.com/subscriptions/{subscriptionId}/providers/Microsoft.Network/locations/{region}/availablePrivateEndpointTypes?api-version=2021-03-01

Output should include the Microsoft.ApiManagement.service endpoint type:

[...]

      "name": "Microsoft.ApiManagement.service",
      "id": "/subscriptions/{subscriptionId}/providers/Microsoft.Network/AvailablePrivateEndpointTypes/Microsoft.ApiManagement.service",
      "type": "Microsoft.Network/AvailablePrivateEndpointTypes",
      "resourceName": "Microsoft.ApiManagement/service",
      "displayName": "Microsoft.ApiManagement/service",
      "apiVersion": "2021-04-01-preview"
    }
[...]

Disable network policies in subnet

Network policies such as network security groups must be disabled in the subnet used for the private endpoint.

If you use tools such as Azure PowerShell, the Azure CLI, or REST API to configure private endpoints, update the subnet configuration manually. For examples, see Manage network policies for private endpoints.

When you use the Azure portal to create a private endpoint, as shown in the next section, network policies are disabled automatically as part of the creation process

Create private endpoint - portal

1. Navigate to your API Management service in the Azure portal.

2. In the left-hand menu, under Deployment + infrastructure, select Network.

3. Select Inbound private endpoint connections > + Add endpoint.

   

4. In the Basics tab of Create a private endpoint, enter or select the following information:

   Setting	Value
   Project details
   Subscription	Select your subscription.
   Resource group	Select an existing resource group, or create a new one. It must be in the same region as your virtual network.
   Instance details
   Name	Enter a name for the endpoint such as myPrivateEndpoint.
   Network Interface Name	Enter a name for the network interface, such as myInterface
   Region	Select a location for the private endpoint. It must be in the same region as your virtual network. It may differ from the region where your API Management instance is hosted.

5. Select the Next: Resource button at the bottom of the screen. The following information about your API Management instance is already populated:

   • Subscription
   • Resource type
   • Resource name

6. In Resource, in Target sub-resource, select Gateway.

   

7. Select the Next: Virtual Network button at the bottom of the screen.

8. In Networking, enter or select this information:

   Setting	Value
   Virtual network	Select your virtual network.
   Subnet	Select your subnet.
   Private IP configuration	In most cases, select Dynamically allocate IP address.
   Application security group	Optionally select an application security group.

9. Select the Next: DNS button at the bottom of the screen.

10. In Private DNS integration, enter or select this information:

    Setting	Value
    Integrate with private DNS zone	Leave the default of Yes.
    Subscription	Select your subscription.
    Resource group	Select your resource group.
    Private DNS zones	The default value is displayed: (new) privatelink.azure-api.net.

11. Select the Next: Tabs button at the bottom of the screen. If you desire, enter tags to organize your Azure resources.

    1. Select the Next: Review + create button at the bottom of the screen.

12. Select Create.

List private endpoint connections to the instance

After the private endpoint is created and the service updated, it appears in the list on the API Management instance's Inbound private endpoint connections page in the portal.

Note the endpoint's Connection status:

• Approved indicates that the API Management resource automatically approved the connection.
• Pending indicates that the connection must be manually approved by the resource owner.

Approve pending private endpoint connections

If a private endpoint connection is in pending status, an owner of the API Management instance must manually approve it before it can be used.

If you have sufficient permissions, approve a private endpoint connection on the API Management instance's Private endpoint connections page in the portal. In the connection's context (...) menu, select Approve.

You can also use the API Management Private Endpoint Connection - Create Or Update REST API to approve pending private endpoint connectionis.

Optionally disable public network access

To optionally limit incoming traffic to the API Management instance only to private endpoints, disable public network access.

To disable public network access using the Azure CLI, run the following az apim update command, substituting the names of your API Management instance and resource group:

az apim update --name my-apim-service --resource-group my-resource-group --public-network-access false

You can also use the API Management Service - Update REST API to disable public network access, by setting the publicNetworkAccess property to Disabled.

Validate private endpoint connection

After the private endpoint is created, confirm its DNS settings in the portal:

1. Navigate to your API Management service in the Azure portal.

2. In the left-hand menu, under Deployment + infrastructure, select Network > Inbound private endpoint connections, and select the private endpoint you created.

3. In the left-hand navigation, under Settings, select DNS configuration.

4. Review the DNS records and IP address of the private endpoint. The IP address is a private address in the address space of the subnet where the private endpoint is configured.

Test in virtual network

Connect to a virtual machine you set up in the virtual network.

Run a utility such as nslookup or dig to look up the IP address of your default Gateway endpoint over Private Link. For example:

nslookup my-apim-service.azure-api.net

Output should include the private IP address associated with the private endpoint.

API calls initiated within the virtual network to the default Gateway endpoint should succeed.

Test from internet

From outside the private endpoint path, attempt to call the API Management instance's default Gateway endpoint. If public access is disabled, output includes an error with status code 403 and a message similar to:

Request originated from client public IP address xxx.xxx.xxx.xxx, public network access on this 'Microsoft.ApiManagement/service/my-apim-service' is disabled.
       
To connect to 'Microsoft.ApiManagement/service/my-apim-service', please use the Private Endpoint from inside your virtual network. 

Related content

• Use policy expressions with the context.request variable to identify traffic from the private endpoint.
• Learn more about private endpoints and Private Link, including Private Link pricing.
• Manage private endpoint connections.
• Troubleshoot Azure private endpoint connectivity problems.
• Use a Resource Manager template to create an API Management instance and a private endpoint with private DNS integration.