You have an Azure subscription that contains 10 network security groups (NSGs), 10 virtual machines, and a Log Analytics workspace named Workspace1. Each NSG is connected to a virtual machine. You need to configure an Azure Monitor Network Insights alert that will be triggered when suspicious network traffic is detected. What should you do first?

Azure Monitor Network Insights uses a feature called Traffic Analytics to analyze network traffic flow and identify potential threats, such as traffic from malicious IP addresses. The primary data source for Traffic Analytics is Network Security Group (NSG) flow logs. Therefore, the foundational and first step required to enable this analysis is to configure and enable NSG flow logs for the network security groups you wish to monitor. These logs capture IP traffic information flowing through the NSGs, which is then processed to provide insights and trigger alerts on suspicious activity.

A. Deploy Connection Monitor. Connection Monitor is used to test connectivity, latency, and packet loss between endpoints. It does not analyze traffic patterns for suspicious activity.
B. Configure data collection endpoints. Data collection endpoints are used with the Azure Monitor Agent to ingest data into Log Analytics. NSG flow logs use a different mechanism involving a storage account.
C. Configure a private link. A private link provides secure, private connectivity to Azure services. It is a network configuration for access, not a data source for traffic analysis.

1. Microsoft Learn, "Traffic analytics": Under the "Prerequisites" section, it explicitly states: "Network security group (NSG) flow logging enabled for the network security groups you want to monitor." This confirms that configuring NSG flow logs is a mandatory first step.

2. Microsoft Learn, "Azure Monitor Network Insights overview": In the "Traffic" section, it describes the capability: "Traffic Analytics analyzes Network Watcher network security group (NSG) flow logs to provide a comprehensive view of traffic flow in your Azure cloud." This directly links the feature to NSG flow logs as its data source.

3. Microsoft Learn, "Tutorial: Log network traffic to and from a virtual machine using the Azure portal": The tutorial for setting up traffic logging and analysis begins with the section "Enable NSG flow log," demonstrating it is the initial action required.