What is NSGs?

Network Security Groups (NSGs) are a fundamental security feature in Azure (and similar cloud platforms). They act as a virtual firewall, controlling inbound and outbound network traffic to and from Azure resources (like virtual machines, Azure App Service Environments, and virtual networks subnets). NSGs contain security rules that allow or deny network traffic based on various criteria, such as source and destination IP addresses, ports, and protocols. They are commonly used to isolate networks, restrict access to critical resources, and implement a layered security approach.