A VPN grants access to the network, and then filters what can be reached from it.
That order is a decision. It was made a long time ago, by people solving a different problem, and almost nobody has revisited it since. But it is still being paid for — and the license is the smallest number in the story.
What the order costs
Consider what exists in a typical estate purely to constrain something that has already been granted.
Segmentation, to limit where a connected session can go. Micro-segmentation, because segmentation turned out to be too coarse. Network access control, to decide what is allowed to connect in the first place. Monitoring, to record where sessions went. Detection, to notice the ones that went somewhere they should not have. Lateral movement detection, which is a product category that exists because lateral movement is possible.
Every one of those is a sensible purchase in isolation. Each was bought by a competent person for a good reason. Together they represent a substantial share of a security budget, they each carry a console, a license and an owner, and they are all downstream of the same architectural choice: access is granted at the network level first, and constrained afterwards.
None of them are wrong. They are compensating controls, and what they are compensating for is the order.
So when the VPN comes up for renewal and the number looks reasonable, that number is not the cost of the VPN. It is the entry fee.
Why it never gets cheaper
The pattern is worth noticing, because it is the reason this line item grows every year and never shrinks.
Each layer is purchased to address the coarseness of the layer beneath it. Segmentation was too broad, so micro-segmentation. Rules became unmanageable, so a policy engine to manage the rules. Alerts outpaced the team, so a platform to triage the alerts. At no point is anything removed, because the thing beneath is still load-bearing.
This is the same accumulation described in “Stop the madness” — additions layered on additions — arriving here as a budget rather than as an attack surface. It is not a spending problem. The spending is the symptom.
Reverse the order
If a session reaches one application and no route onto the network exists, there is nothing to segment and nowhere to move sideways.
That is not a claim that detection and monitoring become unnecessary — you still want to know what happened, and no serious estate runs without them. It is a claim about how much work they are being asked to do. A control that constrains movement is doing very different work in an estate where movement was never possible in the first place.
The question this puts to any access product is a simple one: after it has decided, what does the session actually hold? A credential for one application, or a position on a network with an access control list drawn around it?
Where this is sharpest
Industrial and critical infrastructure environments, which is part of why they keep appearing in breach reporting.
Access into a plant network is frequently a VPN and a shared credential, with segmentation as the only thing standing between a contractor’s laptop and a controller. The access control was never designed. It was inherited — from a period when the plant network was not reachable from anywhere that mattered, and the assumption survived the thing that made it true.
The shape is identical in an office estate. It is simply less consequential when it fails.
And it has to be the whole estate
One caution, because this is where the argument is usually half-implemented.
Reversing the order for the applications that were easy to move, while the difficult ones stay behind a network-level path, does not reverse anything. It produces two orders running in parallel — per-application access for one group of systems, grant-then-filter for the rest — and the compensating control stack stays exactly where it was, because it is still holding up the half that did not move.
The saving is not in changing the order for some things. It is in not needing the compensating layer at all, and that only happens when there is nothing left underneath it. Which means the enforcement point has to be able to front the cloud and SaaS applications the organization has already modernized, the internal web applications, and the awkward ones that resisted every previous attempt — from one place.
The objection, which is correct
The VPN works. Everyone depends on it. Replacing it touches the whole organization at once, and the project would be judged on the week it went wrong rather than the two years it went right.
All of that is true, and it is why an architecture that everyone involved agrees is wrong outlives the people who inherited it. It is also why the sensible move is not a replacement. Total Access Control goes in alongside what is there and takes one population at a time — the mechanics of that are in “Why do you still have a VPN?”, and the point here is only that the order can be changed incrementally. It does not require a cutover date.
The order decides the blast radius — including for things you cannot see
There is a reason to settle this before the next wave of products arrives rather than after.
AI agents increasingly act inside sessions that a person opened legitimately. Whether any given one is identified, registered and well behaved is a separate question, and a real one. But what it can reach if it is not identified is decided entirely by the order.
On a grant-then-filter path, an agent operating inside an authenticated session inherits the network that session was placed on, and the compensating controls are the only thing standing in the way — the same controls that were already struggling with human sessions. On a per-application path, it inherits the application. Nothing about the agent changed. The ceiling did.
Products being built to govern agents will address identification. Very few of them will change what a session holds, and that is the half that determines the damage.
The question this raises
If someone had valid credentials for your VPN this afternoon, how far would they get before anything stopped them?
If the honest answer is “further than I would like, but segmentation would probably contain it”, that is the compensating control doing the work the architecture should be doing — and you are paying for both.