Industrial DMZ
An industrial dmz is a buffer zone that sits between office and factory networks. You build it by placing two firewalls around shared servers to stop direct traffic. Many teams set up this zone to share sensor data with office apps. They often grant broad network roles so engineers can log in and fix machines. When roles are too broad, one stolen key lets an attacker reach plant gear. How an industrial dmz works in network architecture The Purdue Model places this buffer zone at Level 3.5 bet
DMZ: the complete guide
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An industrial dmz is a buffer zone that sits between office and factory networks. You build it by placing two firewalls around shared servers to stop direct traffic. Many teams set up this zone to share sensor data with office apps. They often grant broad network roles so engineers can log in and fix machines. When roles are too broad, one stolen key lets an attacker reach plant gear.
How an industrial dmz works in network architecture
The Purdue Model places this buffer zone at Level 3.5 between IT and OT. An outer firewall blocks raw traffic coming from the office side. An inner firewall guards the control network where factory machines run. No packet can cross straight from the office to the plant floor. All traffic must stop inside the buffer zone first.
Teams place data historians, patch servers, and remote login hosts in this middle zone. The plant network pushes sensor logs up to the shared historian server. Office workers then read that copy of the data from the outer side. When vendors need to fix a machine, they log in to the middle zone. From there, they open a second session into the plant network. Each firewall checks the source address, target port, and user role before traffic passes.
What the native setup solves and what it misses
This two-firewall design stops malware from spreading straight from office laptops to factory controllers. It keeps plant traffic local and hides control systems from outside scans. Network teams can shut down the whole buffer zone if an alert fires. This setup does a great job of controlling which host can talk to another.
Still, firewall rules and login roles only check who starts a session. Once an engineer or vendor logs in, the firewall cannot read the live commands. A user with a valid role can run a bad query or drop tables. Shared admin keys on middle servers also make it hard to track individual actions. Network logs show that a session happened, not what queries or scripts ran inside. Plus, static database results can expose emails, phone numbers, or card numbers to contractors.
DMZ: architecture patterns and best practices
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Steps to tighten roles and traffic in the buffer zone
Start by removing any rule that lets traffic skip the middle zone. Check every firewall rule and delete unused ports or wide address ranges. Split your middle zone into smaller subnets for data servers and remote login hosts. Make sure the plant side initiates data pushes whenever your protocol allows it.
Next, replace shared admin accounts with personal user logins tied to your directory. Set up multi-factor checks for anyone entering the buffer zone from the office. Limit each role to the exact server and port needed for the task. Review your firewall logs every week to spot failed login tries or odd traffic.
Govern statements and responses across databases and APIs
Good config and scoped roles are needed setup. They do not check single queries in flight or mask sensitive fields in returned rows. Across Postgres, MySQL, SQL Server, MongoDB, ClickHouse, Kubernetes APIs, SSH, and internal HTTP endpoints, hoop.dev sits inline in the protocol beside each supported service as an open-source proxy, a sidecar for your database or API. For every query or command an AI agent or engineer runs against production, hoop.dev decides to pass, mask, block, or hold it for human approval.
First, hoop.dev guardrails block banned queries before they run or hold risky ones for review, and hoop.dev data masking rewrites matched sensitive values in responses in memory. Furthermore, hoop.dev holds SOC 2 Type II and is open source on GitHub.
Frequently asked questions
Why do you need two firewalls for a factory buffer zone?
Two firewalls let you separate office rules from plant rules. Even if one firewall fails, the second barrier still blocks direct network traffic.
Can cloud apps read data straight from the plant floor?
No, cloud apps should never reach into the lower control levels. Send plant data to a replica server in the buffer zone first.
How do vendors fix machines without a direct network path?
Vendors log in to a host inside the buffer zone first. From that middle host, they open a controlled session to the plant machine.