An Invisible Layer of Defense: Why On-Prem Inline Security Belongs in Front of Your Firewall

Pretty much every organization these days has a next-gen firewall (NGFW). Many of them with multiple locations will architect some form of SD-WAN solution to maximize efficiency and security. On paper, those organizations have their edge security locked down. 

And yet. NGFWs are the kings of multi-tasking, from identity to remote access, edge policy enforcement, and security. This complexity has its tradeoffs: The modern public attack surface is a dangerous mix of wide-open ports, exposed services, misconfigurations, and vulnerabilities in the edge devices themselves.

The Problem with Relying on a Single Edge Device

It’s a frustrating reality, but one all of us have been forced to accept. Security will always be at odds with the day-to-day needs of the organization. Firewalls are one of the clearest places this contradiction shows up, as they commonly sacrifice security for legitimate business use-cases.

Every exception is a trade-off. Every VPN service, remote desktop connection, and exception expands the attack surface. These processes are a natural part of normal business operations, but that doesn’t make them any less dangerous.

Every change creates an opportunity for misconfiguration. This problem is endemic, even for the most well-known platforms. To make matters worse, according to the Verizon DBIR 2025, edge vulnerability exploitation jumped from 3% to 22% of all vulnerability exploitation breaches in a single year, an 8x increase, and the Mandiant M-Trends 2025 report points to edge devices owning the top four most exploited vulnerabilities in 2024.

Clearly, the existing approach to edge security no longer holds water.

The Public Attack Surface is Bigger than Your Firewall

And then there’s the fact that your public attack surface can be much, much larger than merely the firewall. Your exposed surface includes everything with a public IP or open port. That means the NFGW itself, VPNs, points of presence (POPs), and everything else that answers a probe. 

Shadow IT can live on the Edge, too. A Texas county recently installed their first Nomic Outpost, and within minutes of deployment, alerts were signaling an old exploit on a forgotten web service, still answering on Port 80. Needless to say, they ripped that server offline as fast as they could.

Making the Case for an Independent Inline Security Layer 

So, if a firewall alone, even implementing the latest and greatest SASE tools, isn’t enough to properly manage exposure, what do organizations need?

They need a security tool that doesn’t rely on the firewall at all: An independent, inline security layer that sits between the router and the firewall, first line of defense, agnostic to whatever’s behind it, inspecting and dropping malicious traffic before it ever reaches the firewall or anything behind it.

It isn’t just a safety net for misconfigurations, vulnerabilities, and all the other problems with firewall-focused edge security. Dropping 70% of all inbound traffic, it also makes firewalls more efficient. This inline defense layer reduces all the noise hitting the firewall, so its logs, alerts, and rule-processing get cleaner.

Network Cloaking Reduces the Attack Surface

A concept we call “Network Cloaking” is what ensures organizations stay protected, even as the public attack surface changes. There are two components: The architecture and the methodology. 

First, the architecture: This security layer sits independent of the rest of the network stack, out in front, buffering the public attack surface behind it from malicious scans, exploits, and reconnaissance.

Second, the methodology: Even if your NGFW drops malicious traffic or denies initial attacker communication, there’s usually nothing stopping that attacker from continuing to probe and recon the rest of your public attack surface and unearthing that next open port or exposed service. Better for a dedicated layer to drop all traffic to and from attacking IPs, hiding your edge and letting the NGFW do the routing, network segmentation, and other heavy lifting it’s meant to do these days.

Most edge attacks happen because they’re cheap, scalable, and the victims are seen as low hanging fruit. Network Cloaking changes that.

You Could Build It Yourself

Now, I would be remiss if I failed to mention that you could build an independent inline security layer yourself. That would most likely mean using pfSense or OPNsense as the platform, Suricata or Snort for traditional IPS and network security monitoring (NSM), and threat intel feeds like the CINS Army feed for known-bad IPs. But it takes a lot of effort to keep all of that going. If your feeds aren’t current and automated, they can do more harm than good. 

An out-of-date threat feed ruleset can give false confidence while missing live threats. You could argue otherwise, but I think that’s worse than having no feed at all.

Why Nomic Outpost is the Simpler Solution

Taking the DIY path is a legitimate option. Don’t let me dissuade you from taking it if you are so inclined. But managing it is a full-time job. And, as an SMB, you likely don’t have the resources.

That’s why we built Nomic Outpost. It’s that same Network Cloaking architecture, managed and maintained, so you don’t have to waste any of your limited time, budget, or resources. It’s an independent inline security layer with no reliance or affect on your existing infrastructure.

Sound like something you might be interested in? Watch a demo today.

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