pfSense

pfSense is open source network security software, described by Netgate as rapidly becoming the world's most trusted open source network security solution with thousands of enterprises using it, available as a free download and as pfSense Plus on Netgate physical and virtual appliances, including versions running in Amazon Web Services and Microsoft Azure.

Being open source changes the economics of this category in a way worth understanding before comparing it with commercial alternatives.

A commercial next-generation firewall is sold as hardware plus annual security subscriptions, and the subscriptions are what keep threat detection current. pfSense removes the licence cost entirely for the base software, which means an organisation can build a capable firewall on commodity hardware for the cost of the hardware alone.

What that trade actually buys and costs is the honest question. The saving is real and can be substantial across many sites. What is given up is the vendor support relationship, the curated threat intelligence feeds that commercial subscriptions provide, and the ability to escalate to someone contractually obliged to help at three in the morning. In exchange you gain complete configuration transparency and no dependency on a vendor's licensing decisions.

The determining factor is usually staff rather than budget. An organisation with a competent network engineer who understands firewalling gets excellent value. An organisation without one is buying something it cannot configure safely, and a misconfigured firewall is more dangerous than an expensive one because it creates confidence without protection.

Netgate appliances address that directly by providing pfSense Plus with commercial support on supported hardware, which is the middle path for organisations wanting the software without carrying all the operational risk.

Cloud availability through AWS and Azure virtual appliances extends the same configuration to cloud environments, which matters for organisations wanting one firewall approach across on-premise and cloud rather than learning each cloud provider's native controls.

The base software is published as a free open source download, with Netgate appliances and pfSense Plus sold commercially.