EXPLORE THE CURRICULUM
Your learning map
See how it fits together. Find the lesson you want to learn next.
30 lessons · Networks
Reset filtersL0Network foundationsStep 31–4010 lessons
- 031 Understanding IP Addresses Completely — Neighborhood Name and House NumberExplain that an IPv4 address is actually a 32-bit number
- 032 MAC Addresses and ARP — The Real Address on the WireExplain the difference between IP and MAC addresses from three perspectives (who assigns it, does it change, w…
- 033 DNS — The Internet's Phone BookExplain that DNS is a hierarchical system that converts "name → IP"
- 034 Ports and Services — Room Numbers Inside the BuildingExplain what a port is and how it differs from an IP (building and room number)
- 035 TCP Deep Dive — The Art of the HandshakeExplain what it means that TCP is "connection-oriented"
- 036 UDP and ICMP — The Courier Who Throws and the Status HotlineExplain the difference between TCP and UDP by the criterion "is it meaningful to receive the missing piece aga…
- 037 Routing and Gateways — Follow the Letter's JourneyExplain what a router and a hop are
- 038 NAT and Home Routers — The Secret of the Disguise-Managing DoorstepRecite the three private IP ranges and tell whether a given address is private or public
- 039 The OSI 7 Layers — A Map for Placing Nine PiecesRecite the OSI 7 layers in order and describe each layer's role in one line
- 040 Level 0 Comprehensive Test — Examining YourselfPinpoint what you know and what you don't across all of Level 0
L1Network toolsStep 77–859 lessons
- 077 Socket Communication 1 — A TCP echo Server and ClientExplain in code that a socket is "a communication endpoint between program and program"
- 078 Socket Communication 2 — A Multi-Client Chat ServerExplain that a thread is "a flow of execution sharing memory inside the same process"
- 079 The Port Scanner — A Scout That Finds Open DoorsExplain, with a tool you built yourself, that the principle of port scanning is "attempting a connection (conn…
- 080 Introduction to Scapy — The Handmade Packet WorkshopRead from show() output that a packet is a multi-layer structure stacked as Ethernet/IP/TCP/data
- 081 Mastering nmap — The Standard Tool of ReconnaissanceChoose the right nmap option (-sT/-sS/-sV/-O/--script) for the situation
- 082 Project — Network Map and Risk AssessmentDefine the three terms — asset, attack surface, and risk — and apply them in practice
- 083 Wireshark 1 — Capture and Filters, the Microscope of NetworksPick a network interface and start and stop a capture
- 084 Wireshark 2 — Dissecting Protocols and Detecting AnomaliesFind the TCP 3-way handshake as three packets in a real capture
- 085 Project — HTTP vs HTTPS Comparison ReportOpen a plaintext web server locally and prove with a capture that requests/responses ride in packets letter fo…
L2Networks & authenticationStep 156–16611 lessons
- 156 MITM Primer — ARP Spoofing 1: A Protocol with No ID CardExplain the structure and fields of ARP requests (who-has) and replies (is-at)
- 157 ARP Spoofing 2 — Bidirectional Interception and the End of PlaintextExplain the difference between one-way and bidirectional spoofing in terms of "what becomes visible"
- 158 Packet Sniffing Advanced — The Two Faces of Filters and Reassembling ConversationsExplain the difference between capture filters (BPF syntax) and display filters (Wireshark syntax), and use ea…
- 159 DNS Spoofing and bettercap — Swapping Out the Phone BookExplain the structure of DNS query/response packets (question record and answer record)
- 160 SSL/TLS and HSTS — The ID-Card System That Stops the Man in the MiddleExplain the TLS handshake's stages (Client Hello → certificate → key agreement → encrypted communication)
- 161 Firewalls and iptables — Designing the Gatekeeper's RulesExplain the meaning of chains (INPUT/OUTPUT/FORWARD) and targets (ACCEPT/DROP/REJECT)
- 162 Proxies and Anonymity — The Art of Hiding Behind a Stand-In, and Its LimitsExplain the difference between a forward proxy and a reverse proxy by "whom it represents"
- 163 SSH Tunneling and Port Forwarding — Loading Other Roads onto an Encrypted PassageExplain the directional differences of local (-L), remote (-R), and dynamic (-D) forwarding with diagrams
- 164 Enumeration Tools, Complete Review — A System for Flipping Every StonePick the right tool for each enumeration situation (external network / web / host internals) without hesitatio…
- 165 Password Spraying and Credential Stuffing — Attacks That Walk Sideways Past the LockClassify online password attacks into vertical (brute force) / horizontal (spraying) / reuse (stuffing)
- 166 Wireless Security: WPA2 and the Handshake — Key Material Floating in the AirExplain the four messages of the WPA2 4-way handshake in order