Azure Firewall Best Practices.

Next-Generation Firewalls, cloud native firewalls, and network security groups…oh my? Modern network security certainly has its tech, tools, and providers, and with it, some pretty intimidating choices.  

Cloud Native Firewalls is one of these avenues to bolster an organization’s security posture, and can provide specialized solutions tailored to cloud-based applications and workloads.  

One of these technologies, Microsoft Azure Firewall, is often used by businesses to achieve comprehensive network security across hybrid infrastructure. And if you’re an Azure Firewall – and Azure Network Security – kind of person, this resource is for you.  

Get Sure About Azure and Azure Services 

For the uninitiated, Azure is Microsoft’s cloud computing platform. Azure offers access, management, and the development of applications and services through global data centers. It is also viewed as a primary cloud vendor and remains incredibly popular and common with many an organization’s security infrastructure. Perhaps yours? 😉   

With that kind of credibility, and usage, it is critical for Azure Firewall to protect the endless interactions between the public cloud and the internet. From malware prevention to unauthorized access to attack detection, the Azure Firewall is tasked with providing real-time alerts, advanced threat protection, and security signals. So, as one could imagine, you want to make sure it’s properly configured.  

How to Best Configure Your Azure Firewall  

With all of this responsibility – and pressure – at the hands of your Azure Firewall, organizations are charged with ensuring said firewall is best set up for success. We’ll cover a few areas of Azure cloud firewall configuration that can make that happen.  

Initial Setups and Fundamentals  

Before getting into how the firewall will look/operate, you’ll need to figure out where the firewall will be focusing its efforts.   

Start by determining the firewall zones. These zones could be one’s internal network, a demilitarized zone (DMZ), or public network. Each firewall zone will have associated firewall interfaces, which serve as the points of connection to these zones.   

The next step to configuration should involve the who part of the equation, and that’s where Access Control Lists (ACLs) play a key role. ACLs manage permissions, allowing only authenticated user accounts to access particular areas of an organization’s network. The big part of this configuration, as you can imagine, is setting up user accounts and defining permissions.  

It’s also 2024, so let’s be realistic about virtual machines, remote access, RDP, and the Azure Virtual Network (VNET) service endpoint. You’re going to need to enable Virtual Private Network (VPN) and Network Address Translation (NAT), especially if your organization will engage with private IP addresses behind your firewall.  

And at the end of it all, be sure your firewall interfaces are aligned with your switch – or router – interfaces. It’s essential for maintaining steady network performance.  

Defining and Implementing Firewall Rules Effectively  

With the people and initial tech setup in place, it’s important to understand the parameters in which they are operating, and firewall rules (and application rules) serve as that core of firewall configuration.   

Firewall rules determine which inbound traffic and outbound traffic is to be allowed (or blocked). Such determinations can be hooked to private/public IP addresses, TCP/UDP port numbers, application IDs, user IDs, and types of traffic (for example, HTTP for web servers and associated destination ports).   

All About That (Network Rule) Base  

As alluded to in earlier resources, there’s plenty of work that can be done with regard to rules and rule sets. Remove unused rules and objects (for example, redundant IP addresses) from the rule bases to improve efficiency of the firewall network AND ensure – and aid – audit readiness. Streamline the Azure firewall rule base; it’ll reduce complexity and overlapping to avoid vulnerabilities. Lastly, be sure to prioritize frequently used Azure firewall policy rules, and ensure they align with Windows operating systems so incoming traffic is handled efficiently.  

Thankfully, firewall management tools exist that provide a clear overview of these rules, which can simplify – and perhaps automate – setup and ongoing monitoring.   

Managing and Monitoring Network Traffic  

Speaking of monitoring, let’s dig a little deeper into the data flowing in and out of one’s network and in Azure’s IDPS. So how do you handle it all? Our best practices may sound simple on the surface, but we understand it takes some effort, so we’ll lay that out here too.   

It starts with removing bad traffic and cleaning up the network. How? Start notifying server administrators about servers, PCs, or specific applications hitting the firewall directly with outbound denied requests – ranging from DNS and NTP to SMTP and HTTP – and malware-infected data packets. Then begin the process of reconfiguring these to avoid sending unauthorized outbound traffic, and you’ll start to wrap the benefits of a decreased load on the firewall and enhanced internet speed.  

Some other pointers, since this particular area of best practices has some layers:   

Distribute unwanted traffic filtering across firewalls and routers. Why? It will balance performance and the effectiveness of the security system. Why else? This practices enhances your network performance, making it resilient to issues the likes of denial of service (DNS) attacks.   

Minimal logging is your friend! Use it to manage broadcast traffic in order to improve traffic flow AND bandwidth.  

Common Mistakes That Can Be Avoided  

We’re not saying there’s bad advice out there, but there are some important considerations and hesitations that should be made when configuring an Azure Firewall. We won’t make your decisions for you, but we can strongly recommend steering clear of a few potential Azure firewall functionality pitfalls. These are some best practices to keep things running on solid ground with minimal “drops” or surprises.  

Evade DNS objects that call for constant DNS lookups on all traffic. This is a biggie, especially if you’re a small business relying on steady internet connections.  

Segregate firewalls from VPNs. This will help manage VPN traffic and reduce strain on the network firewalls.  

Relegate UTM features from the firewall to dedicated solutions. Some examples of these features include antivirus and intrusion prevention software.  

Don’t “set and forget” when it comes to software. Regularly update to the newest version(s) to ensure stateful packet inspection, and, of course, minimize security system vulnerabilities.   

The best way to avoid mistakes, though, is of course through testing. With your Azure Firewall appropriately set up, conduct penetration testing to ensure it’s functioning correctly. This is one of the best ways to monitor performance AND make necessary adjustments as required.   

Always be Improving  

Remember, successful firewall configuration goes beyond the initial setup. It involves regular firewall rule base cleanup, comprehensive firewall audit, and understanding the firewall rules lifecycle. This ongoing process is key to maintaining a robust and secure network.  

It may seem daunting at first, but firewall optimization is a continuous process. That said, there are tools that can help with this ongoing task. Tools – like ones that enable firewall network topology visualization – can be particularly beneficial in this ongoing task.  

So Let’s Get to It!

Yes, there’s a lot that goes into setting up an Azure Firewall, while also setting up said firewall for success. Between rules, zones, interfaces, access control, VPN and NAT, monitoring performance, and a whole host of other must-dos, Tufin’s Azure resources, security services, and solutions like firewall management and firewall management automation can simplify these processes. Book a demo to take these for a spin and see what might make the most sense for your network and organization.  

Wait, What’s This About Automation?

Yes, configuring a firewall can be an intricate process, but automation has the potential to simplify it. Firewall management automation solution can streamline the configuration process, ensuring optimal network security and performance.