Introduction - Networking fundamentals

This chapter explains what happens when someone types www.google.com into a web browser

Chapter 4: Networking fundamentals

This chapter covers networking fundamentals by way of tracing the movement of a data packet from one host to another across the Internet - highlighting key network devices and network protocols involved, data encapsulation/de-encapsulation against the OSI model layers, and how switches and routers facilitate communication on the network.

This chapter will help students:

• Map networking protocols and devices to their functions and OSI model layers.

• Compare switches (intra-network) and routers (inter-network) in facilitating communication.

• Describe data encapsulation/de-encapsulation across OSI model layers.

• Understand what happens when someone types www.google.com into a web browser.

• Identify common network protocols (e.g., HTTP, TCP/IP, DNS) and their security implications.

• Relate network layers (OSI/TCP/IP models) to vulnerabilities and mitigation techniques.

Topics covered in this chapter

Network devices - including clients, servers, switches, routers, and firewalls - and their functions.

The Open Systems Interconnection (OSI) model layers and their role in data flow.

Host to host communication in networking (intra- and inter-network data flow).

How switches facilitate communication within a network (MAC tables and VLANs).

How routers facilitate communication between networks (routing and ARP tables, and subnets).

Network protocols and their functions (ARP, FTP, SMTP, HTTP, SSL, TLS, HTTPS, DNS, and DHCP).

Network layers within the OSI model in the context of vulnerability and mitigation (e.g., L1 sniffing, L2 ARP spoofing MITM, L3 ICMP flooding, L4 TCP SYN flooding, L5 session hijacking, L6 phishing, and L7 DNS spoofing).