Computer Networks Study Notes

Application Layer Protocols Overview

A survey of the protocols that let applications talk to each other over a network, and how they fit above the transport layer.

Common Network Attacks

Recognize how common network attacks like DoS, MITM, ARP spoofing, DNS spoofing, and port scanning work — and how to defend against them.

Common Networking Pitfalls

Frequent mistakes and misconceptions in networking, explained so you can recognize and avoid them.

Data Link Layer Basics

How raw bits are organized into frames for reliable node-to-node delivery on the same network segment.

DHCP

How DHCP automatically assigns IP configuration to devices joining a network through the four-step DORA process.

DNS: The Domain Name System

How DNS translates human-friendly domain names into IP addresses through a distributed hierarchy of resolvers and servers.

Error Detection and Correction

How networks detect and, in some cases, correct bit errors introduced during transmission.

Ethernet Standards

Common Ethernet naming and speeds (10BASE-T to Gigabit and beyond) and why CSMA/CD is largely obsolete on modern switched networks.

Firewalls Basics

Understand how packet-filtering, stateful, and application-layer firewalls inspect traffic differently to enforce security policy.

FTP and Email Protocols

How FTP moves files using separate control and data connections, and how SMTP, POP3, and IMAP differ for sending and retrieving email.

HTTP and HTTPS

The request/response protocol behind the web, its core methods, and how TLS secures it as HTTPS.

Hubs, Switches, and Routers

Learn how hubs, switches, and routers operate at different OSI layers and how they shape collision and broadcast domains.

Introduction to Computer Networks

Learn what a computer network is, why we build them, and the core benefits they provide.

IP Addressing and Subnetting

Master IPv4 addressing and CIDR subnetting with a fully worked, hand-verified example.

IPv4 vs IPv6

Compare the two IP versions across address size, notation, and how IPv6 changes the need for NAT.

Load Balancers Basics

Learn how Layer 4 and Layer 7 load balancers distribute traffic across servers using algorithms like round robin and least connections.

MAC Addressing and Switching

How 48-bit MAC addresses identify devices and how switches learn and use them to forward frames.

Network Address Translation (NAT)

See how NAT rewrites private IP addresses to public ones, conserving IPv4 addresses and hiding internal network structure.

Network Layer Basics

Learn how the network layer handles logical addressing, packet forwarding, and fragmentation to move data across networks.

Network Performance Concepts

Understand how bandwidth, throughput, latency, jitter, and packet loss differ and how they interact to determine real-world network experience.

Network Security Basics

Learn the core principles that keep networks safe: confidentiality, integrity, availability, and the controls that enforce them.

Network Troubleshooting Tools

Learn how ping, traceroute, netstat/ss, and nslookup/dig work under the hood to diagnose connectivity, routing, and DNS issues.

Network Types and Topologies

Compare network types by scale (PAN, LAN, MAN, WAN) and topologies by structure and tradeoffs.

Common Networking Interview Questions

The most frequently asked computer networking interview questions with concise, technically accurate answers.