Network Security Groups (NSGs) in Azure provide a way to filter network traffic to and from Azure resources. NSGs contain a list of security rules that allow or deny network traffic based on various criteria, such as source IP address, destination IP address, protocol, and port number.
Setting effective NSG rules in Azure is critical for securing your resources and preventing unauthorized access. Here are some best practices for setting effective NSG rules:
- Start with a deny-all rule: Start with a default deny-all rule that blocks all incoming traffic to your resources. Then, add rules that explicitly allow necessary traffic.
- Use service tags: Azure provides service tags that allow you to group IP addresses associated with Azure services. Using service tags simplifies NSG rule creation and management.
- Limit the scope of rules: Only allow traffic that is necessary for your resources to function. For example, if your web server only needs to accept HTTP and HTTPS traffic, create NSG rules that allow only those protocols and ports.
- Log denied traffic: Configure NSGs to log denied traffic. This provides visibility into attempts to access your resources and helps identify potential security threats.
- Regularly review and update rules: Regularly review NSG rules to ensure that they are still necessary and effective. Update rules as needed to reflect changes in your environment and security requirements.