NETWORK SECURITY LAB
Explore network boundaries, firewall decisions and suspicious traffic through safe, fictional simulations.
OFFLINE SIMULATIONSFIREWALL RULESLOG INVESTIGATIONv1.001 | Understand the network
This simplified model shows how a perimeter firewall controls traffic entering a private network. Real networks also need host firewalls, segmentation and monitoring.
Internet
Untrusted network
Firewall
Rule enforcement
Internal network
Server + workstation
02 | Firewall decision simulator
Choose a fictional traffic flow, then inspect the matching firewall decision. The rules are deliberately simplified and evaluated in order.
| Priority | Example rule | Action |
|---|---|---|
| 1 | Internet → Public web server, HTTPS (443) | Allow |
| 2 | Internal LAN → Admin interface, HTTPS (443) | Allow |
| 3 | Guest Wi-Fi → Any internal destination | Deny |
| 4 | All other inbound traffic | Deny by default |
Illustrative policy only. This is not a real firewall configuration or live network test.
03 | Traffic log investigation
Review fictional log events. Select an event to learn whether it suggests normal activity, a policy block or something worth investigating.
| Time | Source | Destination | Event | Inspect |
|---|---|---|---|---|
| 09:02 | 198.51.100.14 | Web · 443 | Allowed HTTPS | |
| 09:05 | 203.0.113.77 | Admin · 22 | Denied SSH | |
| 09:08 | 192.0.2.45 | Workstation · 3389 | Denied RDP | |
| 09:10 | 10.0.0.25 | Admin · 443 | Allowed HTTPS | |
| 09:13 | 203.0.113.77 | Admin · 22 | Repeated denials |
All addresses are fictional documentation or private-range examples. No packets are sent.
04 | Defensive decision challenge
A public web server needs to serve visitors securely. Which inbound rule is the most appropriate?
Allow only the traffic that a service genuinely needs.
Separate guest devices, user systems and administrative services.
Investigate unusual patterns, not merely isolated blocked packets.
Educational simulation only
This tool operates locally in the browser with fixed fictional examples. It does not scan IP addresses, connect to servers, inspect your actual network or change firewall rules. Do not treat its outputs as a security assessment.
Explore threats. Test your defenses. Understand digital security.
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