Frequently asked questions about networking in Azure Functions

This article lists frequently asked questions about networking in Azure Functions. For a more comprehensive overview, see Functions networking options.

How do I set a static IP in Functions?

Deploying a function in an App Service Environment is currently the only way to have a static inbound and outbound IP for your function. For details on using an App Service Environment, start with the article Create and use an internal load balancer with an App Service Environment.

How do I restrict internet access to my function?

You can restrict internet access in a couple of ways:

  • IP restrictions: Restrict inbound traffic to your function app by IP range.
    • Under IP restrictions, you are also able to configure Service Endpoints, which restrict your Function to only accept inbound traffic from a particular virtual network.
  • Removal of all HTTP triggers. For some applications, it's enough to simply avoid HTTP triggers and use any other event source to trigger your function.

Keep in mind that the Azure portal editor requires direct access to your running function. Any code changes through the Azure portal will require the device you're using to browse the portal to have its IP whitelisted. But you can still use anything under the platform features tab with network restrictions in place.

How do I restrict my function app to a virtual network?

You are able to restrict inbound traffic for a function app to a virtual network using Service Endpoints. This configuration still allows the function app to make outbound calls to the internet.

The only way to totally restrict a function such that all traffic flows through a virtual network is to use an internally load-balanced App Service Environment. This option deploys your site on a dedicated infrastructure inside a virtual network and sends all triggers and traffic through the virtual network.

For details on using an App Service Environment, start with the article Create and use an internal load balancer with an App Service Environment.

How can I access resources in a virtual network from a function app?

You can access resources in a virtual network from a running function by using virtual network integration. For more information, see Virtual network integration.

How do I access resources protected by service endpoints?

By using virtual network integration you can access service-endpoint-secured resources from a running function. For more information, see virtual network integration.

How can I trigger a function from a resource in a virtual network?

You are able to allow HTTP triggers to be called from a virtual network using Service Endpoints.

You can also trigger a function from all other resources in a virtual network by deploying your function app to a Premium plan, App Service plan, or App Service Environment. See non-HTTP virtual network triggers for more information

How can I deploy my function app in a virtual network?

Deploying to an App Service Environment is the only way to create a function app that's wholly inside a virtual network. For details on using an internal load balancer with an App Service Environment, start with the article Create and use an internal load balancer with an App Service Environment.

For scenarios where you need only one-way access to virtual network resources, or less comprehensive network isolation, see the Functions networking overview.

Next steps

To learn more about networking and functions: