Azure NSG

 Azure Network Security Groups (NSGs) are a fundamental element of Azure's network security and access control capabilities. NSGs act as a distributed firewall for controlling traffic to and from Azure resources, including Virtual Machines (VMs), virtual networks, and subnet-level traffic. Here's an overview of Azure NSGs and their key features:

1. Rule-Based Access Control:
• NSGs allow you to define inbound and outbound security rules based on source and destination IP addresses, ports, and protocols.
• You can create rules to allow or deny specific types of traffic to and from your Azure resources.
2. Default and Custom Rules:
• NSGs come with default rules that allow outbound traffic and deny all inbound traffic by default.
• You can create custom rules to fine-tune your network security settings based on your specific requirements.
3. Priority-Based Rule Evaluation:
• Rules in NSGs are evaluated based on priority. The lower the priority value, the higher the rule's precedence.
• Rules with the same priority are evaluated in ascending alphabetical order.
4. Multiple Assignment:
• You can associate an NSG with multiple Azure resources, such as VMs, subnets, or network interfaces, making it easier to manage security policies across a group of resources.
5. Stateful Filtering:
• NSGs provide stateful filtering, which means that if you allow outbound traffic to a specific port, the corresponding inbound response traffic is allowed automatically.
6. Logging and Monitoring:
• NSGs can be configured to log network traffic for analysis and auditing purposes.
• Azure Monitor and Azure Security Center can be used to monitor NSG activity and security recommendations.
7. Integration with Azure Services:
• NSGs can be applied to various Azure resources, including VMs, virtual network subnets, and network interfaces.
• They can also be associated with Azure Application Gateways and Azure Firewall for additional security.
8. Default and Custom NSGs:
• Azure provides both default and custom NSGs. Default NSGs are automatically created when you create a virtual network and subnet, while custom NSGs are user-defined and can be associated with resources as needed.
9. Inbound and Outbound Control:
• NSGs allow you to control both inbound and outbound traffic to and from Azure resources.
10. Security Rules Logging:
• You can enable logging for NSG rules, which helps in monitoring and troubleshooting network traffic.
11. Dynamic and Static IP Address Support:
• NSGs can have rules based on static IP addresses and dynamic IP addresses.
12. Threat Detection and Mitigation:
• Azure DDoS Protection Standard can be integrated with NSGs to provide enhanced protection against distributed denial of service (DDoS) attacks.

Azure NSGs play a crucial role in securing your Azure resources by allowing you to control traffic flows effectively and implement network-level security policies. They are commonly used to restrict access to VMs, control communication between different parts of your Azure infrastructure, and ensure that only authorized traffic is allowed in and out of your virtual networks.