Extending Your Network – Firewall Configuration Lab

This lab introduces beginners to basic firewall rules and network protection by tasking users with detecting and blocking malicious traffic. Through visual cues and hands-on configuration, we learn how to filter traffic based on ports, a critical first step in securing networks.

---

Lab Objective

“Deploy the static site attached to this task. Malicious traffic is marked red; legitimate traffic is marked green. Block traffic using port 80 to prevent malicious packets from reaching the server 203.0.110.1.”

Your goal: Use a firewall rule to block HTTP traffic on port 80, while allowing safe traffic to pass through.

---

Interactive Scenario WalkthroughLab Environment

• Web-based static lab interface

• Malicious requests marked in red

• Legitimate requests marked in green

• Target server: 203.0.110.1

• Protocol to block: HTTP (port 80)

---

Task Breakdown

• Analyze incoming traffic

• Identify the port carrying malicious requests

• Configure a firewall rule to block that port

• Validate that malicious packets are dropped while legitimate packets continue

---

Action Taken

Inside the simulation, I inspected the packet logs and confirmed that all red (malicious) traffic was being sent via port 80, commonly used for unencrypted web traffic (HTTP).

I then configured the firewall with a rule to:

nginxCopyEditBlock traffic on port 80

---

Outcome

Once the rule was in place, the malicious red packets stopped reaching the destination server 203.0.110.1, while the green packets (safe traffic on other ports) continued uninterrupted. The flag was then revealed:

Flag: THM{FIREWALLS_RULE}

---

Key Concept: Why Block Port 80?

Port 80 is the standard port for HTTP. In real-world networks, attackers often exploit unsecured HTTP traffic. Firewalls can be configured to block such ports, enforce encryption (HTTPS), or segment network zones. This lab helps reinforce:

• Protocol filtering

• Basic firewall rule implementation

• Recognizing malicious port usage

---

Skills Practiced

• Traffic analysis

• Port-based firewall configuration

• Differentiating secure vs. insecure protocols

• Basic security hygiene for web traffic

---

Flag Captured

THM{FIREWALLS_RULE}

Final Thoughts

This short but impactful lab gives a practical taste of what real-world network defense begins to look like. Firewalls remain a frontline defense, knowing how to configure them effectively, even at a basic level, is key for any aspiring cybersecurity professional.