DMZ architecture in Cybersecurity - Step-by-Step Execution

Concept Flow - DMZ architecture

Internet

↓

External Firewall

↓

DMZ Zone

↓

Web Server

↓

Internal Firewall

↓

Internal Network

Traffic flows from the Internet through an external firewall into the DMZ, where public servers reside, then through an internal firewall to the internal network.

Execution Sample

Cybersecurity

Internet -> External Firewall -> DMZ -> Internal Firewall -> Internal Network

Shows the path data takes through the DMZ architecture from outside to inside.

Analysis Table

Step	Source	Firewall Check	Allowed?	Destination
1	Internet	External Firewall	Yes	DMZ
2	DMZ Server (Web)	Internal Firewall	Yes	Internal Network
3	Internet	Internal Firewall	No	Blocked
4	DMZ Server (Mail)	Internal Firewall	Yes	Internal Network
5	Internet	External Firewall	No	Blocked

💡 Traffic blocked if firewall rules do not allow passage.

State Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
Traffic Location	Internet	DMZ	Internal Network	Blocked	Internal Network	Blocked or Internal Network
Firewall Decision	N/A	Allowed	Allowed	Blocked	Allowed	Depends on rules

Key Insights - 3 Insights

Why can't traffic from the Internet go directly to the Internal Network?

Because the internal firewall blocks direct access from the Internet to protect the internal network, as shown in execution_table step 3.

Why do servers in the DMZ have access to the Internal Network?

Because the internal firewall allows specific traffic from DMZ servers to the internal network, as seen in steps 2 and 4.

What happens if the external firewall blocks traffic?

Traffic is stopped before reaching the DMZ, as shown in execution_table step 5.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is traffic from the Internet blocked by the internal firewall?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Check the 'Allowed?' column for 'No' at step 3.

According to variable_tracker, where is the traffic located after step 2?

A Internet

B DMZ

C Internal Network

D Blocked

💡 Hint

Look at 'Traffic Location' after Step 2.

If the external firewall blocks traffic, what is the final traffic location?

A DMZ

B Blocked

C Internal Network

D Internet

💡 Hint

Refer to execution_table step 5 and variable_tracker final state.

Concept Snapshot

DMZ architecture places public servers in a separate zone between two firewalls.
External firewall filters Internet traffic to DMZ.
Internal firewall controls DMZ to internal network access.
Protects internal network from direct Internet exposure.
Allows controlled access to public services.

Full Transcript

DMZ architecture is a security setup where public-facing servers are placed in a special zone called the DMZ. Traffic from the Internet first passes through an external firewall that filters what can enter the DMZ. Inside the DMZ, servers like web and mail servers handle public requests. To protect the internal network, an internal firewall controls traffic from the DMZ to the internal network, allowing only approved connections. Traffic directly from the Internet to the internal network is blocked by the internal firewall. This layered approach helps keep the internal network safe while still providing public services.