Last Updated on July 24, 2025 by Arnav Sharma
Azure application security groups and Azure network security groups are both powerful tools used to protect your applications and resources in Azure. Both the vital for Azure Security and easy to configure.
However, there are some critical differences between NSG and ASG that you should be aware of before deciding which one is right for you.
Application security groups are designed to protect applications, while network security groups are designed to protect networks.
Application security groups can filter traffic to and from an application, while network security groups can control traffic to and from a network. Network Security Group (NSG) filters network traffic between Azure resources in an Azure virtual network. NSGs or network security can be associated with either a network interface, virtual machine interface, or subnet/subnets.
Application Security Groups (ASG) are a feature within Azure that helps simplify the management of Network Security Group (NSG) rules. ASGs can be used to group related applications together and manage their security together.
For example, you could create an ASG for all your web applications and another ASG for all your database applications. You can then add NSG rules to the ASGs that apply to all the applications within that group. This makes it easy to manage the security for all your applications at once.
ASGs can also be nested within other ASGs. This allows you to create a more granular level of security for your applications. For example, you could have an ASG for all your web applications and then create a sub-group within that ASG for all your high-security web applications.
- All network interfaces assigned to an application security group must belong to the same virtual network as the first network interface assigned to the application security group is in.
- If you specify an Application Security Group (ASG) as the source and destination in a security rule, Network Interfaces in both ASGs must exist in the same Virtual Network.
To adequately mitigate security risks, you should designate security groups according to their function instead of using individual IP addresses or ranges of IP addresses.
Azure Firewall vs NSG: Two different security solutions from Microsoft.
Microsoft offers two different security solutions for Azure: Azure Firewall and NSG. Both of these solutions have advantages and disadvantages, so choosing the right one for your needs is essential.
Azure Firewall is a managed firewall service that protects your Azure resources. It is a cloud-based solution that is easy to deploy and manage. Its has a variety of features, like SSL inspection, and inbound and outbound traffic filtering, allow or deny traffic based on a large number of factors.
NSG is a network security group that can be used to control traffic in and out of your Azure resources. It is less scalable than Azure Firewall and provides limited features, but it is easy to deploy and manage.