Azure Firewall vs Network Security Groups (NSGs)

An essential security measure while running workloads on any cloud service is to monitor and manage the incoming and outgoing traffic that uses your resources. The resources can be virtual machines that are running an SQL Server, other web applications, or domain services. Essentially, Microsoft Azure offers two security services to control the traffic that flows in and out of resources. These services are known as Azure Firewall and Network Security Groups (NSGs). This article will discuss how the two differ from each other and how they can be paired up to secure traffic to resources in Azure.

Azure Firewall

Azure Firewall is a network security service to secure network traffic with contents in it. Basically, it intelligently detects the workloads in the VNet and protects the resources from malicious traffic. Azure Firewall is an OSI layer 4 & 7 network security service and is fully managed by Microsoft. To apply the Azure Firewall, we just need to set and configure the rules such as Network rules, Nat rules, and Application rules collection.

Network Security Groups (NSGs)

Azure Network Security Groups (NSGs) is a network security service to refine traffic from and to Azure VNet. It is an OSI layer 3 & 4 network security service. An Azure NSG comprises of several security rules that users can allow or deny. These rules are evaluated based on the 5-tuple hash. This 5-tuple hash takes values from the source IP address, source port number, destination IP address, destination port number, and protocol type in use. You can associate Network Security Groups with a VNet or a VM network interface.

How Azure Firewall Works to Protect your Resources?

Azure Firewall offers various features to ensure optimum control over the network traffic that flows in and out. With built-in high availability, Azure Firewall eliminates the need for Load Balancer configuration. The Availability zones feature enables you to configure Azure Firewall for using availability zones to ensure 99.99 percent availability. Azure Firewall also offers scalability options without any extra costs. You can restrict outbound traffic access by specifying the FQDN of the service. Azure Firewall allows you to create rules to filter network based on source IP, destination IP, port, and protocol. These rules can be assigned either of the Allow or Deny status. With the threat intelligence feature enabled, you can receive alerts on traffic from or to identified malicious IP addresses.

How Network Security Group Works to Protect your Resources?

A Network Security Group (NSG) is the solution provided by Microsoft to protect virtual networks. It allows administrators to comfortably organize, filter, direct, and limit different types of network traffic flows. Any Azure Network Security Group can be configured based on different inbound and outbound rules to allow or deny traffic of a certain type. Every NSG can accommodate an Azure virtual network that needs access to your resources. In order to use a Networks Security Group, you will first have to create it. After you have created an NSG, you will be able to configure its individual rules. A rule can be used to define whether the network traffic that is flowing in our out is safe to be permitted or not.

How Azure Firewall and NSG Differ from Each Other?

We can say that a Network Security Group is a firewall, but a very basic one. It is a Microsoft provided solution to filter traffic at the network layer. On the other hand, Azure Firewall is a robust service with tons of features to ensure maximum protection of your resources and regulate traffic depending upon its authenticity. Azure Firewall is a fully managed firewall that can analyze and filter L3 and L4 traffic, as well as L7 application traffic. Azure Firewall offers the same capabilities as of an NSG, and many more in addition. Azure Firewall supports application FQDN tags, whereas NSG lacks this feature. Another major difference between an NSG and Azure Firewall is that Azure Firewall allows you to mask the source and destination network addresses while NSG doesn’t. Also, there is no threat-intelligence-based filtering option in NSG, whereas this feature is present in Azure Firewall.

Why Shall You Contact App4Rent Today?

In this article, we have discussed two major Azure network security services – Azure Firewall and Azure NSGs. Each service provides security on different network levels. Where NSGs offer security to inbound and outbound network traffic based on basic rules, Azure Firewall uses more intelligence to filter network traffic. You can implement NSG on a virtual machine and, at the same time, deploy Azure Firewall to protect resources running into a VNet. Apps4Rent is a Tier 1 Microsoft CSP and can help you obtain maximum value from Azure Services in minimum investment. We are available 24/7 via phone, chat, and email for any further assistance.