What is Azure Firewall?

I’d like to discuss the recently announced Azure Firewall service that is now just released in GA. Azure Firewall is a managed, cloud-based network security service that protects your Azure Virtual Network resources. It is a fully stateful PaaS firewall with built-in high availability and unrestricted cloud scalability.

It’s in the cloud and Azure ecosystem and it has some of thatbuilt-in capability. With Azure Firewall you can centrally create,enforce and log application and network connectivity policies acrosssubscriptions and virtual networks, giving you a lot of flexibility.

It is also fully integrated with Azure Monitor for log analytics.That’s big because a lot of firewalls are not fully integrated with loganalytics which means you can’t centralize these logs in OMS, forinstance, which would give you a great platform in a single pane ofglass for monitoring many of the technologies being used in Azure.

Some of the features within:

• Built in high availability, so there’s no additional load balances that need to be built and nothing to configure.
• Unrestricted cloud scalability. It can scale up as much as you needto accommodate changing network traffic flows – no need to budget foryour peak traffic, it will accommodate any peaks or valleysautomatically.
• It has application FQDN filtering rules. You can limit outboundHTTP/S traffic to specified lists of fully qualified domain namesincluding wildcards. And the feature does not require SSL termination.
• There are network traffic filtering rules, so you can create, allowor deny network filtering rules by source and destination IP address,port and protocol. Those rules are enforced and logged across multiplesubscriptions and virtual networks. This is another great example ofhaving availability and elasticity to be able to manage many componentsat one time.
• It has fully qualified domain name tagging. If you’re runningWindows updates across multiple servers, you can tag that service as anallowed service to come through and then it becomes a set standard forall your services behind that firewall.
• Outbound SNAT and inbound DNAT support, so you can identify andallow traffic originating from your virtual network to remote Internetdestinations, as well as inbound network traffic to your firewall publicIP address is translated (Destination Network Address Translation) andfiltered to the private IP addresses on your virtual networks.
• That integration with Azure Monitor that I mentioned in which allevents are integrated with Azure Monitor, allowing you to archive logsto a storage account, stream events to your Event Hub, or send them toLog Analytics.

Another nice thing to note is when you set up an express route or aVPN from your on premises environment to Azure, you can use this as yoursingle firewall for all those virtual networks and allow traffic in andout from there and monitor it all from that single place.

This was just released in GA so there are a few hiccups, but if none of the service challenges effect you, I suggest you give it a try. It will only continue to come along and get better as with all the Azure services. I think it’s going to be a great firewall service option for many.