Zero trust network architecture in Computer Networks - Mini Project: Build & Apply

Understanding Zero Trust Network Architecture

📖 Scenario: You work in a company that wants to improve its network security. The company heard about Zero Trust Network Architecture (ZTNA) and wants to understand its basic components and how it works.

🎯 Goal: Build a simple conceptual model of Zero Trust Network Architecture by defining key elements, setting up access rules, and applying the core principle of 'never trust, always verify'.

📋 What You'll Learn

Define a list of network resources with exact names

Create a variable for the security level threshold

Write a loop to check access permissions based on the threshold

Add a final statement that summarizes the access decision

💡 Why This Matters

🌍 Real World

Zero Trust Network Architecture is used by companies to protect sensitive data by verifying every access request, no matter where it comes from.

💼 Career

Understanding ZTNA is important for network administrators, cybersecurity professionals, and IT managers to design secure systems.

1

Define network resources

Create a list called network_resources containing these exact strings: 'Email Server', 'File Storage', 'HR Database', 'Public Website'.

Computer Networks

# Create the list of network resources
# Your code here

Hint

Use square brackets to create a list and include all four resource names as strings.

2

Set security level threshold

Create a variable called security_threshold and set it to the integer 3. This will represent the minimum security level required to access sensitive resources.

Computer Networks

network_resources = ['Email Server', 'File Storage', 'HR Database', 'Public Website']
# Set the security level threshold
# Your code here

Hint

Assign the number 3 to the variable named security_threshold.

3

Check access permissions

Create a dictionary called resource_security_levels with these exact key-value pairs: 'Email Server': 4, 'File Storage': 3, 'HR Database': 5, 'Public Website': 1. Then write a for loop using variables resource and level to iterate over resource_security_levels.items(). Inside the loop, create a condition that checks if level is greater than or equal to security_threshold.

Computer Networks

network_resources = ['Email Server', 'File Storage', 'HR Database', 'Public Website']
security_threshold = 3
# Create the dictionary and loop to check access
# Your code here

Hint

Use a dictionary to map each resource to its security level. Then loop through the dictionary items and check if the level meets or exceeds the threshold.

4

Summarize access decisions

Inside the if condition, add a line that sets a variable access_decision to the string "Access granted to " + resource. Add an else block that sets access_decision to "Access denied to " + resource. This completes the basic Zero Trust check.

Computer Networks

network_resources = ['Email Server', 'File Storage', 'HR Database', 'Public Website']
security_threshold = 3
resource_security_levels = {'Email Server': 4, 'File Storage': 3, 'HR Database': 5, 'Public Website': 1}
for resource, level in resource_security_levels.items():
    if level >= security_threshold:
        # Set access_decision for granted access
        # Your code here
    else:
        # Set access_decision for denied access
        # Your code here

Hint

Use string concatenation to build the access decision message inside the if-else blocks.

Practice

1. What is the main principle of Zero Trust Network Architecture?

easy

A. Never trust, always verify every access request

B. Trust all devices inside the network by default

C. Allow unrestricted access to internal resources

D. Use a single password for all users

Solution

1. Step 1: Understand the core idea of Zero Trust

   Zero Trust means no implicit trust is given to any user or device, even inside the network.

2. Step 2: Identify the correct principle

   The principle is to verify every access request before allowing it.

3. Final Answer:

   Never trust, always verify every access request -> Option A

4. Quick Check:

   Zero Trust = Verify every request [OK]

Hint: Remember: Zero Trust means always verify, never trust [OK]

Common Mistakes:

• Assuming internal devices are trusted by default
• Thinking Zero Trust allows open access inside network
• Confusing Zero Trust with simple password policies

2. Which of the following is a correct feature of Zero Trust Network Architecture?

easy

A. Allow all devices to communicate freely once inside the network

B. Trust users based on their IP address alone

C. Use micro-segmentation to limit access to resources

D. Disable multi-factor authentication for ease of access

Solution

1. Step 1: Review Zero Trust features

   Zero Trust uses micro-segmentation to divide the network and limit access to only necessary parts.

2. Step 2: Identify the correct feature

   Micro-segmentation restricts lateral movement and improves security.

3. Final Answer:

   Use micro-segmentation to limit access to resources -> Option C

4. Quick Check:

   Micro-segmentation = Limited access [OK]

Hint: Micro-segmentation limits access inside network [OK]

Common Mistakes:

• Believing all devices are trusted inside network
• Ignoring multi-factor authentication importance
• Trusting users based only on IP addresses

3. Consider this scenario: A user tries to access a sensitive file in a Zero Trust network. The system checks the user's identity, device health, and location before granting access. What is the likely outcome if the device is found to be unpatched and vulnerable?

medium

A. Access is logged but allowed without restrictions

B. Access is granted because the user identity is verified

C. Access is granted but with limited permissions

D. Access is denied due to device health not meeting policy

Solution

1. Step 1: Understand Zero Trust access checks

   Zero Trust verifies multiple factors including device health before access is allowed.

2. Step 2: Apply policy to unpatched device

   An unpatched, vulnerable device fails health checks, so access is denied.

3. Final Answer:

   Access is denied due to device health not meeting policy -> Option D

4. Quick Check:

   Unhealthy device = Access denied [OK]

Hint: Unhealthy devices fail checks, access denied [OK]

Common Mistakes:

• Assuming identity verification alone grants access
• Thinking partial access is allowed despite vulnerabilities
• Ignoring device health in access decisions

4. A network administrator implements Zero Trust but notices users can access resources without verification. What is the most likely error in the setup?

medium

A. All devices are placed in a single trusted zone

B. Micro-segmentation is not properly configured

C. Multi-factor authentication is not enforced

D. User identities are verified but device health is ignored

Solution

1. Step 1: Analyze the symptom

   Users access resources without verification, meaning trust boundaries are missing.

2. Step 2: Identify configuration mistake

   Placing all devices in one trusted zone removes segmentation and verification.

3. Final Answer:

   All devices are placed in a single trusted zone -> Option A

4. Quick Check:

   Single trusted zone = No verification [OK]

Hint: No segmentation means no verification [OK]

Common Mistakes:

• Assuming MFA alone fixes all access issues
• Ignoring network segmentation importance
• Believing device health checks fix trust zone errors

5. A company wants to apply Zero Trust principles to secure remote work. Which combination of actions best supports this goal?

hard

A. Use VPN for all access, trust devices inside VPN, no further checks

B. Implement continuous user verification, device health checks, and micro-segmentation

C. Allow access based on user role only, ignore device security

D. Rely on firewall rules to block external threats, no internal controls

Solution

1. Step 1: Identify key Zero Trust actions for remote work

   Zero Trust requires continuous verification of user identity, device health, and limiting access via segmentation.

2. Step 2: Evaluate options for best fit

   Implement continuous user verification, device health checks, and micro-segmentation includes continuous verification, device checks, and micro-segmentation, covering core Zero Trust needs.

3. Final Answer:

   Implement continuous user verification, device health checks, and micro-segmentation -> Option B

4. Quick Check:

   Continuous checks + segmentation = Zero Trust [OK]

Hint: Combine verification, device checks, and segmentation [OK]

Common Mistakes:

• Trusting devices just because they use VPN
• Ignoring device security in access decisions
• Relying only on perimeter firewalls