Network Protocols Overview

Overview

Networks use rules called network protocols to ensure data reaches the correct destination.
Protocols define order of delivery and data structure for communication between devices.
Example scenario: accessing a recipe website illustrates multiple protocols working together.

Transmission Control Protocol (TCP)
- Establishes a connection between two devices and streams data reliably.
- Verifies both devices before further communication via a "handshake."
Address Resolution Protocol (ARP)
- Resolves the MAC address of the next router or device in the path.
- Ensures packets are forwarded to the correct hardware on the local network.
Hypertext Transfer Protocol Secure (HTTPS)
- Secure method for web browsers to request and receive web pages from servers.
- Uses encryption to protect data exchanged between client and server.
Domain Name System (DNS)
- Translates domain names into IP addresses.
- DNS server lookup provides the IP address used as the destination for packets.

You enter a domain name (e.g., www.yummyrecipesforme.org) in the browser.
DNS resolves the domain name to an IP address for the website server.
TCP initiates a handshake to establish a reliable connection with the web server.
ARP finds the MAC address of the next hop (router or device) to forward packets.
HTTPS is used to securely request and receive the webpage content.
Packets travel through routers and network devices using these protocols in sequence.

HTTPS provides encryption using SSL/TLS to protect data from malicious actors.
Protocol choice affects confidentiality and integrity of network communications.
Security analysts must understand common protocols to evaluate and secure networks.

Term	Definition
Protocol	Set of rules for how devices format, order, and transmit data.
TCP	Connection-oriented protocol that streams data and verifies endpoints.
Handshake	Initial TCP exchange that authenticates and establishes a connection.
ARP	Protocol to map IP addresses to MAC addresses on a local network.
DNS	Service/protocol that translates domain names to IP addresses.
HTTPS	Secure HTTP that encrypts web traffic using SSL/TLS.
SSL/TLS	Cryptographic protocols used to encrypt and secure communications.

Review each protocol’s purpose, typical ports, and layered model placement in upcoming material.
Practice tracing a packet flow (DNS → TCP handshake → ARP resolution → HTTPS request).
Study SSL/TLS basics to understand how HTTPS provides confidentiality and integrity.