Demilitarized Zone
A demilitarized zone (DMZ) is a network segment that isolates publicly accessible systems from an organization's internal network to improve security.
“A physical or logical subnetwork that contains and exposes an organization's external-facing services to an untrusted network, commonly the Internet.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Demilitarized Zone?
Systems exposed to the internet, such as web servers, are placed in the DMZ so attackers cannot directly access internal systems if those servers are compromised.
Network isolation: The DMZ separates external and internal networks.
Security layer: Firewalls control communication between network zones.
Testing considerations: Security testing verifies firewall rules and access restrictions.
Real World Example
A regulated product team is preparing a release where Demilitarized zone appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Demilitarized zone as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Demilitarized zone and similar ideas.
The page becomes useful in practice because Demilitarized zone is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Demilitarized zone in the context of ISTQB terminology?
Question 2
A tester needs to explain Demilitarized zone to a non‑technical stakeholder. Which approach is MOST appropriate?
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