How to whitelist the Function app in Azure SQL Database
I need to configure Azure SQL Database firewall settings so that it can only be accessed by my Azure Function app. The problem is I'm running the app in a consumption plan, and as far as I know, the outbound IP address(es) can change even when I don't take any actions.
Is there a way to whitelist the app so that I protect the database from unwanted connections?
I thought of whitelisting by Azure region since everything is hosted in the same region, but then how do I guard against other apps in the same region? That's why I'm thinking of using specific IP addresses. My only concern with this approach is, I don't know if other function apps can share the same outbound IP addresses as my own.
P.S. Currently, my firewall settings deny public network access and allow Azure services to connect only.
There are several ways to achieve this.
You may want to integrate VNet or get static IP addresses for your Azure Functions
Image from: https://learn.microsoft.com/en-us/azure/azure-functions/functions-networking-options
However, what I've seen from your comments you don't want to go the premium plan.
The last thing I can suggest you implement Managed Service Identity.
The idea behind this, instead of connecting the database with connection string, you connect to the database with the access token that you granted. You can't get the access token if you are not in the same Identity.
This tutorial explains the general idea with App Service: https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-connect-msi
and this tutorial pretty much covers what do you really want to achieve.
Good luck!