AP® Cybersecurity · Side quest before Unit 3
Before Unit 3: Networking Basics
Unit 3, Securing Networks, assumes you already know how data moves across a network. These three short sessions, about 60 minutes in total, teach only the networking that Unit 3's CED statements rely on: hosts and packets, the devices that move them, the addresses inside them, and how wireless networks announce themselves.
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Session 1 · 20 minutes
Networks: hosts, packets and the devices that move them
A network is a set of devices, called hosts, connected so they can exchange data.
- Distinguish a local area network, a wide area network and the internet.
- Identify hosts, servers and network data ports, and explain why an open data port is a risk.
- Distinguish the internal network from external networks and locate the boundary between them.
- Identify a packet's header and payload, and distinguish a packet from a frame.
- Describe the role of a switch, a router, a wireless access point and a firewall, and identify the default gateway.
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Session 2 · 25 minutes · includes a simulator
Addresses: MAC, IP, ARP, DNS and ICMP
Every connected device has two addresses: a media access control (MAC) address, which names its network card on one local link, and an internet protocol (IP) address, which locates it across networks.
- Describe a MAC address and distinguish it from an IP address.
- Identify the network portion, range and broadcast address of a /24 network, and classify an address as private or public.
- Explain how ARP pairs IP and MAC addresses, and how ARP poisoning redirects traffic and is detected.
- Explain how DNS turns a name into an IP address, and how DNS poisoning leads to credential harvesting.
- Describe ICMP and ping, and explain a smurf attack.
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Session 3 · 15 minutes
Wireless basics: access points, SSIDs and beacon frames
A wireless access point connects devices to the wired local area network (LAN) by radio and announces the network's name, its service set identifier (SSID), in beacon frames several times a second.
- Describe how a wireless access point announces and provides a network.
- Explain why a signal that reaches beyond the building is a risk, and how organizations limit it.
- Recognize an evil twin, a rogue access point and a jamming attack, and how each is detected.
You are ready for Unit 3 when you can
- explain why an open network data port or a signal outside the building lets an adversary reach the LAN;
- say which parts of a captured packet an adversary can read when the payload is encrypted;
- tell a switch from a router, and find the default gateway;
- read a /24 address range and spot its broadcast address;
- explain how ARP poisoning and DNS poisoning work, and the sign that detects each;
- tell an evil twin from a rogue access point.
Everything else in Unit 3, such as firewalls, segmentation and wireless encryption, is taught inside the Unit 3 topics themselves.