Configure Azure Storage firewalls and virtual networks
5 minutes
5 Questions
Configuring Azure Storage firewalls and virtual networks is a critical security task in the Azure Administrator Associate curriculum, designed to protect data at the network layer. By default, Azure Storage accounts accept connections from clients on any network. To secure the resource, administrat…Configuring Azure Storage firewalls and virtual networks is a critical security task in the Azure Administrator Associate curriculum, designed to protect data at the network layer. By default, Azure Storage accounts accept connections from clients on any network. To secure the resource, administrators switch the default network access setting from 'All networks' to 'Selected networks,' establishing a deny-by-default posture.
Once restricted, access is granted through two primary mechanisms:
1. **IP Address Rules:** These allow traffic from specific public IPv4 addresses or CIDR ranges. This is typically used to grant access to on-premises corporate networks or specific external clients connecting over the internet.
2. **Virtual Network (VNet) Rules:** This method utilizes Service Endpoints. By enabling the 'Microsoft.Storage' service endpoint on a specific subnet within an Azure VNet, administrators can whitelist that subnet in the storage firewall. This ensures that traffic between Azure resources (like Virtual Machines) and the storage account travels exclusively distinctively over the Azure backbone network, rather than the public internet. This enhances security by isolating traffic types.
Furthermore, administrators must configure **Exceptions**. The 'Allow trusted Microsoft services' option is essential; when enabled, it grants specific Azure platform services—such as Azure Backup, Azure Monitor, and Site Recovery—access to the storage account even when strict firewall rules are active.
Proper configuration ensures that any request originating from outside the allowed IP ranges or subnets is rejected with a '403 Forbidden' error, effectively minimizing the attack surface and preventing authorized data exfiltration.
Mastering Azure Storage Firewalls and Virtual Networks for AZ-104
Why is this important? Security is a primary domain in the AZ-104 exam. By default, Azure Storage accounts accept connections from clients on any network. To secure your data, you must limit who can communicate with the storage account. Configuring firewalls and virtual networks ensures that traffic is restricted to trusted sources only, minimizing the attack surface and meeting compliance requirements regarding network isolation.
What is it? This is a network security layer applied specifically to the Storage Account resource. It allows you to filter network traffic based on the incoming IP address (IPv4) or the originating Azure Virtual Network (VNet) subnet. It essentially acts as an access control list (ACL) for network requests attempting to reach your blobs, files, queues, or tables.
How it works The configuration follows a hierarchy of rules: 1. Default Action: You generally start by changing the default network access rule from Allow access from all networks to Deny (or "Selected networks"). 2. VNet Service Endpoints: You can whitelist specific Azure VNet subnets. For this to work, the subnet must have the Microsoft.Storage Service Endpoint enabled. 3. IP Address Ranges: You can whitelist specific public internet IP ranges using CIDR notation. Note that private IP ranges (RFC 1918) are not allowed in the firewall rules because the storage account is accessed via a public endpoint unless Private Links are used. 4. Exceptions: You can enable the "Allow trusted Microsoft services to access this storage account" setting (e.g., Azure Backup, Azure Site Recovery, Azure Monitor).
How to answer questions regarding Configure Azure Storage firewalls and virtual networks in an exam When faced with a scenario, first identify the security requirement. If the question asks to restrict access to a specific corporate office, look for answers involving IP firewall rules. If the question asks to secure traffic from an Azure VM to Storage without using a public IP, look for Service Endpoints or Private Endpoints. Analyze the order of operations: usually, the answer involves denying all traffic first, then explicitly adding the allowed networks.
Exam Tips: Answering Questions on Configure Azure Storage firewalls and virtual networks
• Service Endpoint Prerequisite: If a question asks why a subnet cannot be added to the storage firewall allowed list, the answer is often that the Microsoft.Storage service endpoint has not been enabled on that specific subnet yet.
• Trusted Microsoft Services: A common trick question involves an Azure service (like Azure Backup) failing to access a locked-down storage account. The solution is usually checking the box for "Allow trusted Microsoft services to access this storage account" in the 'Exceptions' section.
• Static IPs vs. Dynamic IPs: If you are whitelisting on-premises clients, remember you typically need their public-facing IP addresses/ranges, not their internal LAN IPs.
• Storage Explorer: If a question mentions an administrator cannot access the storage account using Azure Storage Explorer after firewall rules were applied, remember that the administrator's client IP must be added to the firewall allow list.
• Precedence: Remember that specific Deny rules generally do not exist in this context; rather, you set the default to Deny, and then create Allow rules. If traffic does not match an Allow rule, it is blocked.