STUDY GUIDE · GKU 5
Network security study guide (Cybersecurity)
This unit treats the network as both an attack surface and a control point. The first part builds the model a defender needs: the OSI and TCP/IP layers, what each layer adds and addresses, the difference between TCP and UDP, how a packet is routed and rewritten hop by hop, and how addresses, masks, gateways, DNS and DHCP fit together. It then turns to operating a network — VLANs, trunks, routing, address translation, access lists, and the tools that show what is actually happening: ping, traceroute, name lookups, packet capture, flow records, SNMP and port scanning. The last section of the first part covers the protocols that carry trust in modern networks — TLS, DNSSEC, IPsec, 802.1X, routing protocol authentication, software-defined and cloud networks, IPv6 and VPNs — and the ways each is attacked. The second part is defence: the standard attack families and their mitigations, monitoring with IDS, IPS, SIEM and flow data, access control and segmentation, risk-based selection of controls under a budget, and incident response for a network breach. Every section opens with a quick-revision card, and the worked examples run from easy to exam level.
Structured by the official ETEC subject standard for this topic: every listed topic and learning outcome, with formulas, figures and worked examples. The full sections are available to members in the app.
SKU 5.1 · Basic networking and protocols
Networking models, architectures and protocols
The layers and what each one adds, the devices and addresses at each layer, TCP against UDP, the three-way handshake, how routing rewrites a frame at every hop, the application protocols a defender must know, and subnet arithmetic.
Network operation and administration
How a network is configured and kept under control — VLANs and trunks, routing, DHCP, DNS, NAT and ACLs — and the tools that show what it is doing, from ping and traceroute to packet capture, flow records, SNMP and port scanning.
Advanced network protocols and security in modern networks
TLS and certificate validation, DNSSEC and encrypted DNS, IPsec, 802.1X and EAP, routing protocol authentication, software-defined and cloud networking, IPv6 and VPNs, and the attacks that target each.
SKU 5.2 · Network defense and administration
Network threats and attack mitigation
The standard attack families — sniffing, spoofing, man-in-the-middle, replay, SYN flood and DDoS, scanning, VLAN hopping, rogue access points, routing attacks and command-and-control — and the defences that actually address each one.
Network policies, risk and incident management
Turning security intent into enforceable policy: acceptable use, access control, defence in depth, risk-based choice of controls under a budget, maintenance and change windows, and the phases of incident response for a network breach.
MORE CYBERSECURITY GUIDES
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