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Why Can’t Azure VMs Communicate Across Different VNets By Default?
Learn why Azure VMs in different VNets cannot communicate by default for your AZ-500 exam. Understand the network isolation principle and discover how to connect separate VNets using VNet peering or a VPN Gateway for secure cross-VNet communication.
Question
Azure VMs can communicate across VNETs by default.
A. TRUE
B. FALSE
Answer
B. FALSE
Explanation
The correct answer is B. FALSE. Azure Virtual Networks (VNets) are fundamentally designed as isolated network boundaries, meaning virtual machines in different VNets cannot communicate with each other by default.
VMs on subnets within the same VNET have connectivity. Communication across VNETs requires VNET peering or VPN connectivity.
The Principle of VNet Isolation
A Virtual Network in Azure represents a private, isolated network space in the cloud. This isolation is a core security and architectural feature. It ensures that workloads, applications, or environments (e.g., development, staging, production) deployed in separate VNets cannot interfere with or access one another unless explicitly configured to do so. While VMs on different subnets within the same VNet can communicate by default (subject to Network Security Group rules), this connectivity does not extend beyond the VNet’s boundary.
Enabling Cross-VNet Communication
To allow communication between VMs in different VNets, an administrator must intentionally create a connection using one of the following methods.
- VNet Peering: This is the most common and highest-performance method for connecting two VNets. It establishes a direct, low-latency, high-bandwidth connection over the private Microsoft backbone network. Traffic between peered VNets does not traverse the public internet. VNet peering can be established between VNets in the same region (Regional VNet Peering) or in different Azure regions (Global VNet Peering).
- VPN Gateway: A VNet-to-VNet connection can be established using Azure VPN Gateways. This involves creating a gateway in each VNet and establishing an encrypted IPsec tunnel between them, typically over the public internet. This method is often used when VNet peering is not an option or when encryption across the connection is a strict requirement. It generally has higher latency and lower bandwidth compared to VNet peering.
Because enabling this connectivity is a deliberate administrative action, the default state is one of complete isolation, making the original statement false.
Microsoft Certified Azure Security Engineer Associate AZ-500 certification exam assessment practice question and answer (Q&A) dump including multiple choice questions (MCQ) and objective type questions, with detail explanation and reference available free, helpful to pass the Microsoft Certified Azure Security Engineer Associate AZ-500 exam and earn Microsoft Certified Azure Security Engineer Associate AZ-500 certification.