7  Labs and Auto-Grading

A lab is a starting topology, a sequence of steps and objectives the simulator can test.

7.1 The Concept First

NetSim ships five guided labs:

  1. Static addressing and ARP
  2. Routing between networks
  3. Build a stateful firewall
  4. DHCP, DNS and the web
  5. Harden a vulnerable network

Each lab has steps, objectives and quizzes. The Check objectives button runs the checks against the live simulation using real packets. Students see the grader’s probes animate.

The checks are passive or active. Passive checks read device state, such as an interface address or a firewall policy. Active checks send packets, such as a ping, a TCP connect, a DNS query or an HTTP fetch.

A lab is not a quiz with a network attached. It is a scenario with evidence.

7.2 Understanding Through a Driving Test

A driving test does not ask whether you read the manual. It watches you drive.

A NetSim lab watches the packets.

7.3 Discovering the Labs with Your AI Partner

Exploration 1: Map Lab to Concept

Ask the AI to match each lab to a concept.

Here are the five NetSim labs:
[paste them]

For each, name the main concept and one check that proves it. Explain
why a passive check is not enough on its own.

Active checks prove behaviour; passive checks prove configuration.

Exploration 2: Prove the Problem

Ask why a security lab checks the vulnerability first.

Lab 5 asks students to confirm the exposure before they harden it.
Explain why this is better than starting with the fix. What does it
teach about evidence?

The first objective establishes the current state.

Exploration 3: Choose the Verdict

Ask about filtered versus refused.

A firewall drops tcp/22 silently. Another rejects it. Which check should
a hardening lab use, and what does the student learn from the difference?

A silent drop is usually the stronger security outcome.

7.4 From Concept to Practice

A lab record:

Lab Concept Objective Check
1 Addressing and ARP Hosts can ping ping
2 Routing Packet crosses router ping, traceroute
3 Stateful firewall LAN out, internet in blocked tcp, fw-policy
4 Services DHCP, DNS, HTTP work dns, http
5 Hardening Public web reachable, rest filtered tcp filtered

7.5 Build Task

Complete Lab 1 and export the attempt. Then import it and check the objectives again.

7.6 Classroom Connection

Auto-grading gives immediate feedback. It is formative, not a proctored exam. The attempt file is editable, so use it for learning and evidence, not high-stakes assessment.

7.7 Practice Exercises

Exercise 7.1 (Level 1). Name the five labs. Exercise 7.2 (Level 2). Complete Lab 1. Exercise 7.3 (Level 3). Explain one active check. Exercise 7.4 (Level 4). Compare filtered and refused. Exercise 7.5 (Level 5). Export, import and regrade an attempt.

7.8 Chapter Summary

  • A lab is a topology, steps and objectives.
  • Active checks send packets; passive checks read state.
  • The grader’s probes animate.
  • Prove the problem before the fix.
  • Auto-grading is formative.

7.9 Reflection

Before moving on, ensure you:

7.10 Your Learning Journal

  1. Which objective was clearest?
  2. What did the probe prove?
  3. Where is auto-grading weakest?

7.11 Next Steps

The labs work. The next chapter designs one.