Networking and Cyber Awareness
What this domain tests
This domain covers network models, IP addressing, network devices, protocols, and basic cyber security. Expect questions on the OSI/TCP-IP layers, private addresses, ports, malware and phishing.
Core rules
- OSI has seven layers: physical, data link, network, transport, session, presentation, application.
- TCP is connection-oriented and reliable; UDP is connectionless and faster.
- Private IPv4 ranges: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
- Common ports: HTTP 80, HTTPS 443, DNS 53, SMTP 25, SSH 22.
- Devices: hub broadcasts to all ports; switch forwards by MAC address; router forwards by IP address.
- Cyber hygiene: verify sender domains, avoid unknown links, use multi-factor authentication and keep patches updated.
Worked example
How many usable host addresses are in a /27 IPv4 subnet? A /27 leaves 32 − 27 = 5 host bits. Total addresses = 2⁵ = 32. Subtract the network and broadcast addresses: 32 − 2 = 30 usable hosts.
Traps
Do not confuse phishing (fraudulent messages) with pharming (traffic redirection via DNS or hosts manipulation). HTTPS encrypts traffic but does not guarantee that a site is trustworthy. A switch does not route between different IP networks; a router does. Do not count the network and broadcast addresses as usable hosts.
Exam focus
Memorise private ranges, common ports and the layer associated with each device or protocol.