Securing your Azure resources is critical. Both Azure Firewall and Network Security Groups (NSG) play vital roles in managing inbound and outbound traffic. This blog post will guide you through their functionalities, helping you choose the best fit for your needs.
- What is Azure Firewall?
- Azure Firewall Standard
- Azure Firewall Premium
- Azure Firewall Basic
- How does Firewall Azure work?
- What is Azure Network Security Groups (NSG)?
- How does Azure Network Security Groups work?
- Difference between Azure Firewall and Azure Network Security Groups
- Feature Comparison
- FAQs
- Conclusion
Azure Firewall
Managed Firewall Service: Azure Firewall is a cloud-based, intelligent firewall that secures your virtual network (VNet) traffic. It automatically detects workloads and protects them from threats.
- Deep Packet Inspection (DPI): Azure Firewall inspects traffic at Layers 3,4 & 7 of the OSI model, providing granular control over network traffic.
- Threat Intelligence: It leverages Microsoft’s threat intelligence to identify and block malicious traffic in real-time.
- Features:
- Advanced features like SNAT (Source Network Address Translation) and DNAT (Destination Network Address Translation) for managing public IP addresses.
- Service Tags and FQDN Tags for simplified security rule creation.
Checkout the detailed Blog on Azure Firewall
Azure Firewall Standard
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 Premium
Azure Firewall Premium has advanced features such as signature-based IDPS, which provides rapid detection of attacks by searching for specific patterns. These patterns can include byte segments on network connections or known malicious instructions used by malware. More than 58,000 signatures across 50+ categories are updated in real time to prevent new and emerging vulnerabilities. Valid groups include malware, phishing, coin mining, and Trojan horse attacks.
Azure Firewall Basic
Azure Firewall Basic is similar to Firewall Standard with the following important limitations:
Threat only supports Intel Alert Mode
Fixed scaling units backend instance for running programs on two virtual machines
Recommended to estimate competition of about 250Mbps
How does Firewall Azure Work?
Azure firewall offers enough features to provide optimized control over the in and out network traffic. It eliminates the need for Load Balancer configuration because of its high availability. Microsoft Azure ensures 99.99% availability of its resources due to its availability zone feature. It does not charge anything extra for scalability. You pay only for what you use.
Moreover, it also allows restriction on outbound traffic by specifying the FQDN service. You can create your own defined rules using Azure Firewall to filter networks based on source IP, destination IP, port, and protocol. These rules further show the status as Allow or Deny status. It also enables threat intelligence features that can identify malicious IP addresses and irrelevant traffic.
Read Microsoft Defender for Cloud [AZ-500]: Everything You Should Know
Azure Network Security Groups (NSG)
- Basic Firewall for Traffic Filtering: NSG is a stateful firewall that filters traffic entering or leaving your VNet based on pre-defined rules.
- Layer 3 & 4 Security: NSG operates at Layers 3 (network) and 4 (transport) of the OSI model, offering basic traffic filtering.
- Granular Control: You can define rules to allow or deny traffic based on source/destination IP addresses, ports, and protocols.
Check out: Azure Networking
How does Azure Network Security Groups work?
Azure Network Security Group (NSG) is a great solution offered by Microsoft to protect virtual networks. Using this, administrators can comfortably organize, filter, direct, and limit various network traffic flows. You can set different inbound and outbound rules to allow or deny a specific type of traffic to configure Azure Network Security Group. If you want to use Azure Network Security Groups, you need to create and configure individual rules.
You can define any rules required as per the situation, such as to define whether the traffic flowing through the network is safe and needs to be permitted or not.
Also Check: Top 10 Best Practices for Azure Security
Difference Between Azure Firewall and Network Security Group
Feature | Azure Firewall | Network Security Groups (NSG) |
---|---|---|
Service Type | Managed Firewall Service | Stateful Firewall |
Security Level | Advanced (L3, L4, L7) | Basic (L3, L4) |
Threat Intelligence | Yes | No |
SNAT/DNAT | Yes | No |
Application Security | Yes (L7 inspection) | No |
Check out: AZ-500 Exam – Microsoft Azure Security Technologies Certification
Azure Firewall and NSG in Conjunction
Both Azure Firewall and NSG provide security, but combining them increases your defences. NSGs provide you granular control over your VNet, such as allowing RDP access to a certain subnet only from authorised internal machines. Azure Firewall serves as a centralised gateway, monitoring all incoming and outgoing traffic while providing enhanced threat prevention. Together, they provide multilayer security, including granular internal control and a strong exterior security barrier.
Feature Comparison
Let’s compare Azure Firewall and Azure NSG based on their features.
Service Tags
Service tags act as a label that shows a range of IP addresses for specific services such as Data Lake, Container Registry, Azure Key Vault, etc. Both Azure Firewall and NSG provide full support to service tags, but users can’t customize them as Microsoft manages them.
FQDN Tags
Azure Firewall only supports FQDN Tags. They signify a group of fully qualified domain names of Microsoft services such as Windows Update or Azure Backup. FQDN Tags are also managed by Microsoft and cannot be customized.
SNAT
SNAT stands for Source Network Address Translation and is supported by Azure Firewall only. This feature lets the Azure Firewall configure with a public IP address that you can use to mask the IP address of Azure resources that are sent out via the Firewall.
DNAT
DNAT stands for Destination Address Translation, and Azure Firewall supports this feature to translate incoming traffic from the firewall’s public IP address to the private IP addresses of a VNet.
FAQs
What is Azure Firewall?
Azure Firewall is a managed, cloud-based network security service that provides stateful packet inspection, network, and application-level protection, and inbound and outbound filtering for virtual network resources.
What is an Azure Network Security Group (NSG)?
Azure Network Security Group (NSG) is a logical firewall service that filters network traffic between resources in an Azure virtual network and the internet, and between resources within different subnets in a virtual network.
What is the difference between Azure Firewall and Azure Network Security Group (NSG)?
Azure Firewall is a central security service that provides security services for all the resources within a virtual network. It offers granular application-level filtering and threat intelligence-based filtering. On the other hand, Azure Network Security Group (NSG) is a more basic firewall that filters network traffic at the network layer (layer 4) and provides inbound and outbound security rules for individual resources.
Can Azure Firewall and Azure Network Security Group (NSG) be used together?
Yes, Azure Firewall and Azure Network Security Group (NSG) can be used together to provide additional layers of security for virtual networks. Azure Firewall can be used to filter application-level traffic while NSG can be used to filter network-level traffic.
Can Azure Firewall and Azure NSG be used together?
Yes, they can be used together to provide additional layers of security for virtual networks.
What are the benefits of using Azure Firewall?
1. Centralized network security
2. Advanced threat protection
3. Granular application-level filtering.
What are the benefits of using Azure NSG?
Basic network security, inbound and outbound security rules, and easy configuration and management.
What kind of traffic can Azure Firewall filter?
Azure Firewall can filter inbound and outbound traffic for TCP, UDP, and application protocols like HTTP and HTTPS.
When should you use the Azure firewall instead of NSG?
You should use Azure Firewall instead of NSG when you require centralized network security for a virtual network, granular application-level filtering, and advanced threat protection. Azure Firewall is also easier to manage and scale, making it more suitable for larger deployments.
Read: How to prepare for Microsoft Azure Security Technologies [AZ-500] Certification?
Conclusion
Azure Firewall vs NSG battle continues to escalate. Both services are two primary security services from Microsoft. Each service has its perks of security on different network levels. Azure Firewall is an intelligent solution to filter network traffic. On the other hand, Azure Network Security Group provides security to inbound and outbound network traffic based on basic rules. Overall, the Azure Firewall is a complete package and has a slight advantage over Azure Network Security Groups.
References/Related
- Microsoft Azure Security Technologies Certification
- Introduction to Azure Sentinel and Steps to Setup
- What is Azure Backup?- Features, Benefits, Tools & Real-life Examples
- Azure Site Recovery: Benefits, Working, Features, and Implementation
- Top 10 Best Practices for Azure Security
- Azure Security vs AWS Security
- What is Azure security?
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