Understanding the Differences Between Azure Firewall and the VM-Series

Aug 06, 2018
4 minutes

Microsoft recently announced the Azure Firewall (in public preview) as an optional set of extra cost security features that would be deployed in conjunction with Azure Network Security Groups. Key features include:

  • A stateful firewall as a service that provides outbound control over traffic based on port, protocol and/or by manually whitelisting the fully qualified domain name, or FQDN (i.e., www.github.com).
  • Built-in high availability with unrestricted cloud scalability; fully integrated with Azure Monitor for logging and analytics.
  • Price based on each Azure Firewall instance deployed plus bandwidth consumed.

More info can be found here: https://azure.microsoft.com/en-us/services/azure-firewall/

Whereas Network Security Groups are required to enable an Azure VNet, both the VM-Series and Azure Firewall are optional, and as such, customers and partners should understand how they can improve their security posture.


Key VM-Series Differentiators

The VM-Series differs from Azure Firewall by providing customers with a broader, more complete set of security functionality that, when combined with security automation, can help ensure workloads and data on Azure are protected from threats. Specific VM-Series differentiators include:

  • Can be deployed to protect traffic flows in all directions, not just outbound – including inbound, outbound, and east-west.
  • Bi-directional control over applications (web-based and otherwise) not ports, resulting in a threat footprint reduction for improved security and compliance.
  • For allowed traffic, policies can prevent data exfiltration and threats, including vulnerability exploits, known and unknown malware.
  • Granular control over web-based developer resources with PAN-DB URL Filtering – blacklist known malicious categories; whitelist specific developer resource URLs and/or categories.
  • Automation features such as dynamic address groups, external dynamic lists, and HTTP log forwarding to dynamically drive policy updates and ensure that developer environments are protected at the speed of the cloud.
  • Consistent security policies and enforcement across private cloud and public cloud environments.

A more specific comparison can be found in the table below.


General Features VM-Series on Azure Azure Network Security Groups Azure


IP/Port/Protocol-based security X X X
Port ranges used within policy X X X
Source and/or destination within policy X X X
CIDR-based rules X X X
ACL-like features within a policy X X X
Security applied after traffic enters Resource Group X X X
Drop vs. deny distinction within a policy X
Next-Generation Firewall Features  
Policy-based identification and control over thousands of applications; create custom applications; manage unknown traffic based on policy X Web apps only based on whitelisted FQDN
Policy-based, bi-directional SSL decryption and inspection; per-policy SSH control X
Bi-directional control of traffic based on country or geographic region X
QoS: policy-based traffic shaping (priority, guaranteed, maximum) per application, per user, per tunnel, based on DSCP classification X
Zone-based network segmentation and protection X
TCP protocol validation, ensuring that standard three-way handshake is valid X
Additional Features  
Threat Prevention: Prevent known threats (vulnerability exploits, malware and botnets), block polymorphic malware X
Advanced Malware Protection (WildFire®): Detect potential malware, detonate, analyze and automatically deliver protections X
URL Filtering: Control access to web resources based on category and/or specific URL; prevent access to known malicious sites and credential phishing sites X Based on whitelisted FQDN only
File and Data Filtering: Bi-directional control over unauthorized file and data transfer X
Contextual Threat Intelligence (AutoFocus™): Context around attacks, adversaries and campaigns, including targeted industries X
Policy Automation: Tagging to automate policy updates, ingest third-party data directly into policy X
Centralized Management and Visibility: Single pane of glass delivers aggregated logging and event correlation; actionable insight into traffic and threats X
Mobile Security (GlobalProtect™): Extend policy to remote users and devices X
Integration with Azure Security Command Center: Gain more complete visibility into Azure account security status X X X
Scale Out Architectures: Integration with load balancing for scalability and availability X X X

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