Network Security Group Inbound Security Rule: Resources for Azure Exam AZ-900

Network Security Group Inbound Security Rule

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Question

Which resources can be used as a source for a Network security group inbound security rule?

Answers

Explanations

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A. B. C. D.

B

Source or destination:

Any, or an individual IP address, classless inter-domain routing (CIDR) block (10.0.0.0/24, for example), service tag, or application security group.

https://docs.microsoft.com/en-us/azure/virtual-network/network-security-groups-overview

In Microsoft Azure, a Network Security Group (NSG) is a fundamental resource that allows you to control the inbound and outbound traffic to your Azure resources. When creating an inbound security rule for an NSG, you have several options for specifying the source of the traffic. Let's go through each answer option to determine which resources can be used as a source for a Network Security Group inbound security rule.

A. Service Tags only: Service tags are a convenient way to allow or deny traffic based on predefined groups of Azure IP ranges. Azure provides a set of service tags that represent specific Azure services or regions. For example, you can use the "Internet" service tag to allow or deny traffic from the entire internet, or you can use service tags like "AzureStorage" or "AzureSQL" to allow or deny traffic from specific Azure services. However, using service tags alone is not sufficient to cover all possible sources of traffic. Therefore, option A is not the correct answer.

C. Application security groups only: Application security groups (ASGs) are used to group virtual machines (VMs) based on application tiers or other logical groupings. ASGs are primarily used for network security purposes, allowing you to define network security rules based on the membership of VMs in ASGs. While ASGs are useful for defining the destination of traffic in an NSG rule, they are not specifically designed for specifying the source of traffic. Therefore, option C is not the correct answer.

D. IP Addresses only: Option D suggests that only IP addresses can be used as a source for a Network Security Group inbound security rule. While it is possible to define specific IP addresses or IP ranges as the source for a rule, this answer option is not entirely accurate. There are additional resources available for specifying the source of traffic, as explained in the next answer option.

B. IP Addresses, Service tags, and Application security groups: The correct answer is option B. When creating an inbound security rule for a Network Security Group, you can use a combination of IP addresses, service tags, and application security groups as the source of traffic. This allows you to have fine-grained control over the traffic that is allowed or denied to your Azure resources. By specifying specific IP addresses or IP ranges, you can restrict traffic to specific sources. Service tags provide a convenient way to allow or deny traffic from predefined groups of Azure IP ranges, such as Azure services or regions. Additionally, application security groups help you group VMs based on application tiers or other logical groupings, enabling you to define network security rules based on the membership of VMs in ASGs.

To summarize, when creating an inbound security rule for a Network Security Group in Azure, you can use a combination of IP addresses, service tags, and application security groups to specify the source of traffic. This allows you to have flexible and granular control over the inbound traffic to your Azure resources.

Network Security Groups (NSGs) are a fundamental part of Azure networking and allow administrators to control network traffic by defining inbound and outbound security rules. Each NSG contains one or more inbound and outbound security rules that permit or deny traffic based on criteria such as source IP address, destination IP address, port number, and protocol.

To create an inbound security rule for a Network Security Group, you need to specify the source of the traffic that you want to allow or deny. The source can be defined using one of the following resources:

A. Service Tags only B. IP Addresses, Service tags and Application security groups C. Application security groups only D. IP Addresses only

So, the correct answer is B, which means that you can use IP addresses, service tags, and application security groups as a source for an inbound security rule in a Network Security Group.

Service tags represent a group of Azure services that share a common set of IP addresses. By using service tags in a security rule, you can allow or deny traffic to a group of services instead of specifying individual IP addresses.

Application security groups (ASGs) are used to group virtual machines and define network security policies based on the application that the virtual machines are running. By using ASGs in a security rule, you can allow or deny traffic to a group of virtual machines instead of specifying individual IP addresses.

IP addresses are the traditional way to specify the source of traffic in a security rule. You can use single IP addresses, IP address ranges, or CIDR blocks to define the source of traffic.

Therefore, option B is the most comprehensive answer, as it allows you to use all the available resources to specify the source of traffic in a security rule.