Week 2: OSI Model, Reconnaissance, and Network Discovery
Week of Sun, Aug 30 · week closes Sat, Sep 5
This week's items
- Weekly Quiz 2points in Canvas
- Discussion Board 2points in Canvas
- Lab 2points in Canvas
Exact due times are in Canvas. Late assignments are NOT accepted. Complete all assignments before the due date.
Read this week
- TestOut Ethical Hacker Pro — Ch 4–6 — Commercial text; named here for reference.
- RFC 791 — Internet Protocol — Free — the primary source for IPv4 header fields tested on CEH.
- Wireshark Getting Started — Free — official documentation for the network analysis tool used in lab.
Know these cold
- The OSI model has seven layers: Physical (1), Data Link (2), Network (3), Transport (4), Session (5), Presentation (6), Application (7) — attacks and defenses map to specific layers.
- TCP/IP uses four layers: Network Interface, Internet, Transport, Application; IPv4 headers carry source/destination IP, TTL, and protocol fields.
- Passive reconnaissance collects data without touching the target — WHOIS, DNS records, job postings, social media, Google dorks, Shodan — no packets sent to the target's systems.
- Active reconnaissance sends packets to the target and risks detection — ping sweeps, traceroutes, DNS zone transfer attempts, and banner grabbing.
- DNS record types: A (IPv4), AAAA (IPv6), MX (mail server), NS (name server), TXT (SPF/DKIM), PTR (reverse lookup).
- Port ranges: well-known 0–1023 (HTTP 80, HTTPS 443, SSH 22, DNS 53), registered 1024–49151, ephemeral 49152–65535.
- Google dorking uses operators like site:, filetype:, intitle:, and inurl: to discover indexed sensitive information without sending packets.
- Standards: Maryland Blueprint Pillar 3 · CEH v12 Domain 2 (Footprinting) + Domain 3 (Scanning) · PGCC Outcomes 1, 2, 4.
Meerk's quiz — open the Week 2 gate
10 questions, no time limit. 85% on your first attempt in a 24-hour window opens the gate. Retakes inside the window are practice — they help you learn, they don't count. Work alone; the point is to know it, not to have seen it.
Dinner Table Question
Ask at home: You read a server's SSH version from a banner. Did you use an active or passive technique? What is the defender's control?
En español: Lees la versión SSH de un servidor desde un banner. ¿Usaste una técnica activa o pasiva? ¿Cuál es el control defensivo?