Azure Firewall vs NSG: Network Security Comparison and Guide

Azure Firewall is a cloud-native network security solution that provides advanced threat protection and security features. It's designed to protect Azure resources from external threats.

Azure Firewall is a managed service, which means Microsoft handles the maintenance and updates, freeing up your team to focus on other tasks. This also ensures you're always running the latest security features and patches.

NSG, or Network Security Group, is a resource that helps you manage traffic to and from your Azure resources. It's a fundamental building block of Azure security.

Azure Firewall and NSG are both designed to provide network security, but they work in slightly different ways. Azure Firewall offers high availability without the need for a load balancer, ensuring 99.99% availability.

Azure Firewall provides unlimited scalability at no extra cost, so you only pay for what you use. This means you can easily scale up or down as needed without worrying about additional charges.

You can restrict outbound traffic access by specifying a service's FQDN, giving you more control over your network traffic. This is particularly useful for organizations with sensitive data.

Azure Firewall rules can filter incoming traffic based on source IPs, destination IPs, ports, and protocol types, allowing you to customize your security settings. These rules can be assigned an Allow or Deny status, giving you complete control over your network traffic.

On the other hand, Azure Network Security Group (NSG) is a solution that allows administrators to organize, filter, direct, and limit network traffic flows. You can set different inbound and outbound rules to allow or deny specific types of traffic.

Each NSG can be configured according to different inbound and outbound rules to permit or deny a particular type of traffic. This means you have complete control over what types of traffic are allowed into or out of your network.

By enabling the threat intelligence feature, Azure Firewall can identify malicious IP addresses and irrelevant traffic, giving you an added layer of security. This feature can also provide alerts when specific malicious IP addresses are being sent or received.

Azure Firewall and Network Security Groups (NSGs) are both designed to provide security for your virtual network (VNet). Azure Firewall is a cloud-based, intelligent firewall that secures your VNet traffic, while NSGs are a stateful firewall that filters traffic entering or leaving your VNet based on pre-defined rules.

Azure Firewall provides L3-L7 filtering and threat intelligence directly from Microsoft Web Security, while NSGs operate at Layers 3 (network) and 4 (transport) of the OSI model. NSGs can define rules to allow or deny traffic based on source/destination IP addresses, ports, and protocols, while Azure Firewall inspects traffic at Layers 3, 4, and 7 of the OSI model.

Here are the key differences between Azure Firewall and NSGs:

Azure Firewall and NSGs can be used together to provide multilayer security, including granular internal control and a strong exterior security barrier.

A Network Security Group (NSG) is a Microsoft service that simplifies virtual network security by enforcing and controlling network traffic.

NSGs are compatible with an Azure VM's subnets and network interfaces, making it easy to manage network security in the cloud.

NSGs store security rules that provide a mechanism for activating a rule or gaining access to a control list. These rules are used to coordinate, process, and route various forms of network traffic.

The rules in an NSG filter both data traffic, rejecting or permitting traffic based on a five-tuple data, which includes:

These five pieces of information help determine whether network traffic is allowed or blocked.

A Network Security Group (NSG) is a Microsoft service that simplifies virtual network security by enforcing and controlling network traffic.

NSGs are associated with subnets and network interfaces of an Azure VM, making them a crucial component of Azure's virtual network security.

NSGs contain security rules that filter inbound and outbound traffic, denying or allowing traffic based on 5-tuple information: source, source port, destination, destination port, and protocol.

These rules provide IT teams with granular control over network traffic, allowing them to organize, filter, and route different types of traffic.

Here are the key components of an NSG's 5-tuple information:

With NSGs, IT teams can define rules to allow or deny traffic based on these 5-tuple components, providing a high level of security and control over network traffic.

Azure Firewall is a cloud-based, intelligent firewall that secures your virtual network (VNet) traffic. It automatically detects workloads and protects them from threats.

Azure Firewall inspects traffic at Layers 3, 4, & 7 of the OSI model, providing granular control over network traffic. It leverages Microsoft's threat intelligence to identify and block malicious traffic in real-time.

Azure Firewall Standard provides L3-L7 filtering and threat intelligence directly from Microsoft Web Security. Threat-based filtering can alert and deny traffic to and from known IP addresses and domains, and is updated in real-time to prevent attacks.

Azure Firewall Basic is similar to Firewall Standard, but with some limitations. It's still a powerful tool for securing your VNet, but it may not offer the same level of customization as Firewall Standard.

Azure Network Security Groups (NSG) are a stateful firewall that filters traffic entering or leaving your VNet based on pre-defined rules. They operate at Layers 3 (network) and 4 (transport) of the OSI model, offering basic traffic filtering.

Here are some key features of NSG:

You can define rules to allow or deny traffic based on source/destination IP addresses, ports, and protocols. This gives you granular control over your VNet and helps prevent unauthorized access.

Azure Firewall and NSG can be used together to provide multilayer security. NSG provides granular control over your VNet, while Azure Firewall serves as a centralized gateway, monitoring all incoming and outgoing traffic while providing enhanced threat prevention.

NSG is a Microsoft service that simplifies virtual network security by enforcing and controlling network traffic. It's associated with subnets and network interfaces of an Azure VM, and contains security rules that filter inbound and outbound traffic.

Here's what NSG can do:

Azure Firewall offers layer 4 & 7 network security on a virtual network to protect the entire Windows Azure platform. It relies on Microsoft's security policy and can scale depending on the flow of traffic.

Azure Firewall is a comprehensive and robust service with several features to regulate traffic, while NSGs act as a basic firewall that filters traffic at the network layer.

Azure Firewall is adept at analyzing and filtering L3, L4, and L7 traffic, whereas NSG only filters L3 and L4 traffic.

Azure Firewall supports threat-intelligence-based filtering, which NSG can't do. It also supports application FQDN tags, which are used together with application rules to allow the required outbound traffic through the firewall.

Azure Firewall has a function called SNAT – Source Network Address Translation, which allows you to customize it with a Default IP address (PIP) that can mask the IP address of Azure Resources that communicate with the Firewall through the Firewall.

Here are some key features of Azure Firewall and NSG compared side-by-side:

Both Azure Firewall and NSG use service tags to define network access controls, but Azure Firewall also supports application FQDN tags.

Azure Firewall offers robust protection with features like Deep Packet Inspection (DPI) and threat intelligence, which inspects traffic at Layers 3, 4, and 7 of the OSI model. This provides granular control over network traffic.

Azure Firewall's threat intelligence leverages Microsoft's threat intelligence to identify and block malicious traffic in real-time. This is a key feature that sets it apart from Azure NSG.

Azure Firewall also supports application FQDN tags, allowing you to mask source and destination network addresses. This is a feature that Azure NSG does not offer.

Here's a comparison of the security features of Azure Firewall and Azure NSG:

Azure NSG, on the other hand, provides basic firewall functionality and allows you to filter traffic at the network layer. It's a good option for simple network security needs, but it's not as robust as Azure Firewall.

Azure Firewall's threat intelligence-based filtering option is a powerful feature that helps prevent attacks. This is not available in Azure NSG, which relies on more basic filtering rules.