Power Platform integration with Azure APIM previsioned in a VNet internal mode - azure-api-management

We have an Azure APIM provision in a VNet internal mode as described in this article: Connect to an internal virtual network using Azure API Management | Microsoft Docs. We can successfully consume APIs in APIM with Postman and via the Developer Portal, from within the corporate network. However, we don’t have any connectivity between Power Platform and APIM; error message while testing a Custom Connector from Power Apps:
Can someone please point me in the right direction on how to enable comms between Power Platform and Azure APIM in VNet Internal mode. Any links and reference material are highly appreciated.

We decide on provisioning of Applcation Gateway with WAF applied in front of APIM that only allows traffic in from Power Platform. Reference blog post here: https://techcommunity.microsoft.com/t5/azure-paas-blog/apim-with-application-gateway-v1/ba-p/1795180.

Related

Azure APIM VNET (Premium) usecases

After evaluating APIM different tiers, Standard tier seems to be the most suitable one for the workload I am dealing with. I prefer to have a VNet (which is only supported in the Premium version) to isolate and create a proper boundary. But the premium tier is very expensive.
In my setup, my APIM will interact with LogicApps, functions, and microservices deployed on docker in Azure. All these services sit in one VNet where external access is blocked. If I am not connecting to any on-prem service, do I need the VNet for my APIM? Most of the articles talk about premium version and VNet are connecting APIM with on-prem services.
Do we only need to have VNet for my APIM when we are connecting to on-prem services? What are the usecases when one must have APIM in a VNet? Any example would be really appreciated.
UPDATED:
there are a couple of objectives, only access APIs through APIM and use the express route to access on-prem APIs.
The only reason to put APIM into VNET is to make it able making a call to a service in that VNET or make it possible for a client to make a call to APIM, in both cases keeping traffic inside VNET. So it's really about why you want to keep your backend service or clients in VNET.
And isolating your backend APIs from everything but APIM is another scenario. Using VNET here is the strongest guarantee, but comes at a price. Another option is to have authorization (client certificates would work) between APIM and backend, but keep backend publicly available.

How to access Developer Portal when Azure API Management is Internal?

How to access APIM developer portal from internet when APIM is kept internal?
I checked some Microsoft document but did not get it how to do it.
You can Integrate API Management in an internal VNET with Application Gateway.
Combining API Management provisioned in an internal VNET with the Application Gateway frontend enables the following scenarios:
Use the same API Management resource for consumption by both internal
consumers and external consumers.
Use a single API Management resource and have a subset of APIs
defined in API Management available for external consumers.
Provide a turn-key way to switch access to API Management from the
public Internet on and off.
Follow this link for more information : https://learn.microsoft.com/en-us/azure/api-management/api-management-howto-integrate-internal-vnet-appgateway

Securing free API App Service behind consumption API Management

I have created a .NET Core API and deployed it as an App Service in Azure. On top of that, I have an instance of Azure API Management. Now I want the API to be only accessible through the APIM.
During the free testing phase, i restricted the access to the API to the IP of the APIM. As i do not expect my API to have high traffic and to save costs, i now switched to free and consumption tier.
As my APIM uses the consumption tier, there is no static IP that I could use to restrict the API access.
As my App Service uses a free plan, neither VNet Integration nor incoming client certificates are available.
Is there are a way to secure a free App Service API with a APIM in consumption tier with Azure except from implementing it myself?
You have a few options with Consumption SKU in mind:
Basic auth - make APIM send a well known secret and check for that secret in API App.
Client certificate authentication - make APIM use client cert to connect to API App and check for it there.

How to protect the Backend API against calls other than Azure API Management

I have an ASP.NET Core REST API Service hosted on an Azure Web App. I own its source code and I can change it if required.
I am planning to publish REST API Service with Azure API Management.
I am adding Azure AD authentication to the Azure API Management front. So, the API management front is secured. All the steps are is described here.
All good so far. Here is the question (or challange?) :
Considering that my backend REST API Service is hosted on Azure and publicly accessible, how do I protect it against the request calls other than the API Management Calls?
How the backend service knows the identity and AAD group claims of the incoming call and access to its claims?
A link to a code sample or online documentation would be a great help.
Update
While there are some overlaps with the follwoing question:
How to prevent direct access to API hosted in Azure app service
... part of this question is still outstanding:
How the backend service knows the identity and AAD group claims of the incoming call and access to its claims?
You can enable static IP restriction on your WebApp to only allow incoming traffic from the VIP of your APIM Service facing ( keep in mind in some specific scenarios , the VIP may change and will be required to update the whitelist again).
Clients ==> AAD==> VIP APIM Service <==> (VIP APIM allowed) Web App
https://learn.microsoft.com/en-us/azure/app-service/app-service-ip-restrictions

Configuring Application Gateway with API management Azure

I want to establish an connection between API managment and Application Gateway in Azure.
Please can someone provide step by step solution.
What is your scenario? Generally, people set up API Management in an internal VNET and expose a small set of APIs via Application Gateway with a WAF SKU, which is an extra Web application firewall for Front.
Try this: https://learn.microsoft.com/en-us/azure/api-management/api-management-howto-integrate-internal-vnet-appgateway