Azure Bastion is a fully managed Platform as a Service (PaaS) deployed within Microsoft Azure that provides secure and seamless RDP (Remote Desktop Protocol) and SSH (Secure Shell) access to your virtual machines. It is a critical component for implementing secure virtual networking, designed speci…Azure Bastion is a fully managed Platform as a Service (PaaS) deployed within Microsoft Azure that provides secure and seamless RDP (Remote Desktop Protocol) and SSH (Secure Shell) access to your virtual machines. It is a critical component for implementing secure virtual networking, designed specifically to minimize the attack surface of your infrastructure by removing the need for public IP addresses on individual VMs.
Traditionally, administrators accessed VMs by assigning public IPs or maintaining dedicated 'jump box' servers. These methods present security risks; public IPs expose management ports to the open internet, inviting port scanning and brute-force attacks, while jump boxes require constant OS patching and maintenance. Azure Bastion eliminates these issues by functioning as a hardened gateway provisioned inside your Virtual Network (VNet), specifically within a dedicated subnet named 'AzureBastionSubnet'.
When using Azure Bastion, you connect to your VMs directly through the Azure portal using a modern HTML5-based web browser. The traffic is encapsulated over SSL/TLS (port 443), ensuring the session is encrypted and traverse firewalls easily. Because the Bastion host sits within your VNet, it connects to your target VMs using their private IP addresses. Consequently, your VMs remain hidden from the public internet.
Key benefits include: enhanced security (protecting against malware targeting RDP/SSH ports), zero maintenance (Microsoft handles patching, scaling, and hardening), and ease of management. Furthermore, it supports VNet peering, allowing a single Bastion deployment to manage VMs across peered networks in a hub-and-spoke topology, effectively centralizing secure access control within your Azure environment.
Azure Bastion: Secure Management for Virtual Networks
What is Azure Bastion? Azure Bastion is a fully managed Platform as a Service (PaaS) provided by Microsoft that offers secure and seamless RDP (Remote Desktop Protocol) and SSH (Secure Shell) connectivity to your virtual machines. It allows you to connect to your VMs directly through the Azure portal via a web browser.
Why is it Important? The primary function of Azure Bastion is to improve security posture. Traditionally, administrators might expose public IP addresses with open ports (3389 for RDP or 22 for SSH) to the internet to manage VMs. This practice is dangerous as it makes the infrastructure vulnerable to port scanning and brute-force attacks. Azure Bastion eliminates the need for VMs to have public IP addresses for management purposes, ensuring that management traffic remains within the Azure virtual network.
How it Works Azure Bastion is deployed into a specific subnet within your virtual network called the AzureBastionSubnet. Once provisioned, it acts as a gateway. 1. The Connection: You initiate a connection from the Azure Portal in your browser. 2. The Protocol: The traffic is encapsulated over HTML5 and TLS (Transport Layer Security) via Port 443 (HTTPS). This allows the traffic to traverse firewalls easily. 3. The Target: The Bastion host connects to the target VM using the VM's private IP address over RDP or SSH.
Exam Tips: Answering Questions on Azure Bastion For the AZ-104 exam, look for specific keywords and constraints in scenario-based questions:
1. Security Requirements: If a question asks how to securely manage VMs without exposing public IP addresses or opening RDP/SSH ports to the open internet, the answer is almost always Azure Bastion.
2. Subnet Naming: You may face questions about configuration errors. Remember that Azure Bastion requires a dedicated subnet strictly named AzureBastionSubnet. It cannot contain any other resources, and the subnet mask must be at least /26.
3. Network Security Groups (NSGs): Understand the traffic flow. Bastion requires Inbound traffic on port 443 (from the GatewayManager service tag and the Internet) and Outbound traffic on ports 3389 and 22 (to the VirtualNetwork service tag).
4. PaaS Nature: If a question asks about maintaining or patching the 'jumpbox' or 'jump server,' remember that Azure Bastion is PaaS. Microsoft handles the patching and maintenance, not the user.
5. Peering: Azure Bastion supports VNet peering. You do not need to deploy a Bastion host in every VNet; you can deploy it in a hub VNet and manage VMs in spoke VNets.