📘 01 Notes¶
Beginner-friendly, in-depth network security notes organized into 10 modules — from IP addressing all the way to machine-learning-based intrusion detection. Each lesson stands alone, with quick links back to the course flow and a matching practice set.
🧭 Module Dashboard¶
| Module | Focus | Lessons | Start | Practice |
|---|---|---|---|---|
| 01 | Foundations of Network Security | 7 | Start | Practice |
| 02 | TCP/IP Protocols & Packet Analysis | 6 | Start | Practice |
| 03 | Sniffing, Spoofing & MITM | 5 | Start | Practice |
| 04 | TCP/IP Attacks | 5 | Start | Practice |
| 05 | Firewalls & Access Control | 8 | Start | Practice |
| 06 | DNS & DNS Security | 9 | Start | Practice |
| 07 | Cryptography Fundamentals | 8 | Start | Practice |
| 08 | VPN & Secure Tunneling | 6 | Start | Practice |
| 09 | TLS/SSL & Secure Communication | 6 | Start | Practice |
| 10 | Intrusion Detection & ML for Security | 7 | Start | Practice |
📖 Full Lesson Index¶
Module 01: Foundations of Network Security
- [01-01: What Is Network Security?](01-01-what-is-network-security.md) - [01-02: OSI Model Recap](01-02-osi-model-recap.md) - [01-03: TCP/IP Model & Encapsulation](01-03-tcpip-model-and-encapsulation.md) - [01-04: IPv4 Addressing Basics](01-04-ipv4-addressing-basics.md) - [01-05: IPv4 Subnetting & CIDR](01-05-ipv4-subnetting-and-cidr.md) - [01-06: IPv6 Basics & Security](01-06-ipv6-basics-and-security.md) - [01-07: Network Hardware & Attack Surface](01-07-network-hardware-and-attack-surface.md)Module 02: TCP/IP Protocols & Packet Analysis
- [02-01: TCP Fundamentals & 3-Way Handshake](02-01-tcp-fundamentals-and-handshake.md) - [02-02: TCP Flags, Sequence & Ack Numbers](02-02-tcp-flags-sequence-and-ack.md) - [02-03: UDP & Connectionless Protocols](02-03-udp-and-connectionless-protocols.md) - [02-04: Ports, Sockets & Services](02-04-ports-sockets-and-services.md) - [02-05: Reading Packets (Wireshark/tcpdump)](02-05-reading-packets-wireshark-tcpdump.md) - [02-06: IP Spoofing Fundamentals](02-06-ip-spoofing-fundamentals.md)Module 03: Sniffing, Spoofing & MITM
- [03-01: Packet Sniffing Basics](03-01-packet-sniffing-basics.md) - [03-02: Sniffing Tools (Scapy/tcpdump)](03-02-sniffing-tools-scapy-tcpdump.md) - [03-03: ARP Protocol Recap](03-03-arp-protocol-recap.md) - [03-04: ARP Spoofing Attacks](03-04-arp-spoofing-attacks.md) - [03-05: MITM Attacks & Defenses](03-05-mitm-attacks-and-defenses.md)Module 04: TCP/IP Attacks
- [04-01: TCP SYN Flooding](04-01-tcp-syn-flooding.md) - [04-02: IP Spoofing in Attacks](04-02-ip-spoofing-in-attacks.md) - [04-03: TCP Session Hijacking](04-03-tcp-session-hijacking.md) - [04-04: RST Injection](04-04-rst-injection.md) - [04-05: Mitigations (SYN Cookies & Randomization)](04-05-mitigations-syn-cookies-and-randomization.md)Module 05: Firewalls & Access Control
- [05-01: Firewall Concepts & History](05-01-firewall-concepts-and-history.md) - [05-02: Packet-Filtering Firewalls](05-02-packet-filtering-firewalls.md) - [05-03: Stateful Firewalls](05-03-stateful-firewalls.md) - [05-04: Proxy & Next-Gen Firewalls](05-04-proxy-and-next-gen-firewalls.md) - [05-05: iptables Fundamentals](05-05-iptables-fundamentals.md) - [05-06: Writing iptables Rules](05-06-writing-iptables-rules.md) - [05-07: ACLs, DMZ & Segmentation](05-07-acls-dmz-and-segmentation.md) - [05-08: Firewall Limitations & Evasion](05-08-firewall-limitations-and-evasion.md)Module 06: DNS & DNS Security
- [06-01: DNS Infrastructure](06-01-dns-infrastructure.md) - [06-02: DNS Query Process](06-02-dns-query-process.md) - [06-03: DNS Packet Construction](06-03-dns-packet-construction.md) - [06-04: DNS Attack Overview](06-04-dns-attack-overview.md) - [06-05: DNS Cache Poisoning](06-05-dns-cache-poisoning.md) - [06-06: The Kaminsky Attack](06-06-kaminsky-attack.md) - [06-07: Fake Records in Legitimate DNS Response](06-07-fake-records-in-legitimate-response.md) - [06-08: DNS Rebinding Attack](06-08-dns-rebinding-attack.md) - [06-09: Denial-of-Service (DoS) Attacks on DNS](06-09-dos-attacks-on-dns.md)Module 07: Cryptography Fundamentals
- [07-01: Why Cryptography Matters](07-01-why-cryptography-matters.md) - [07-02: Symmetric Encryption Basics](07-02-symmetric-encryption-basics.md) - [07-03: AES & Block Cipher Modes](07-03-aes-and-block-cipher-modes.md) - [07-04: Asymmetric Encryption (RSA)](07-04-asymmetric-encryption-rsa.md) - [07-05: Diffie-Hellman Key Exchange](07-05-diffie-hellman-key-exchange.md) - [07-06: Hashing & Message Integrity](07-06-hashing-and-message-integrity.md) - [07-07: Digital Signatures](07-07-digital-signatures.md) - [07-08: Digital Certificates & PKI](07-08-digital-certificates-and-pki.md)Module 08: VPN & Secure Tunneling
- [08-01: VPN Concepts & Types](08-01-vpn-concepts-and-types.md) - [08-02: IPsec Fundamentals](08-02-ipsec-fundamentals.md) - [08-03: Tunnel vs. Transport Mode](08-03-tunnel-vs-transport-mode.md) - [08-04: Building a VPN Tunnel](08-04-building-a-vpn-tunnel.md) - [08-05: Split Tunneling & Configuration](08-05-split-tunneling-and-configuration.md) - [08-06: VPN Attacks & Weaknesses](08-06-vpn-attacks-and-weaknesses.md)Module 09: TLS/SSL & Secure Communication
- [09-01: TLS History & Versions](09-01-tls-history-and-versions.md) - [09-02: The TLS Handshake](09-02-tls-handshake-walkthrough.md) - [09-03: Cipher Suites](09-03-cipher-suites.md) - [09-04: Certificates in Practice](09-04-certificates-in-practice.md) - [09-05: Common TLS Attacks](09-05-common-tls-attacks.md) - [09-06: TLS Best Practices & HTTPS](09-06-tls-best-practices-and-https.md)Module 10: Intrusion Detection & ML for Security
- [10-01: IDS/IPS Concepts](10-01-ids-ips-concepts.md) - [10-02: NIDS vs. HIDS](10-02-nids-vs-hids.md) - [10-03: Intro to ML for Security](10-03-intro-to-ml-for-security.md) - [10-04: Feature Engineering (NSL-KDD)](10-04-feature-engineering-nsl-kdd.md) - [10-05: SVMs for Classification](10-05-svm-for-classification.md) - [10-06: Building & Training the IDS Model](10-06-building-and-training-the-ids-model.md) - [10-07: Evaluating Detection Models](10-07-evaluating-detection-models.md)🛤️ Recommended Flow¶
- Read the module notes in order — later modules (especially 08 VPN and 09 TLS) lean on Module 07's cryptography concepts.
- Complete the matching exercises.
- Use the quiz hub for recall practice.
- Build a project when the concept needs hands-on reinforcement.