A Quick Guide to Networking Fundamentals

A Quick Guide to Networking Fundamentals

Understanding the basics of computer networking helps every engineer diagnose problems, design systems, and understand how data moves across the internet. Here’s a clean, simple overview of the core concepts.

IP Addresses

An IP address identifies devices on a network.

• Public IP – used to communicate on the internet.

• Private IP – used inside local networks.

• IPv4 – 32-bit, about 4.3 billion unique addresses.

• IPv6 – 128-bit, virtually unlimited address space.

• Static IP – stays the same unless manually changed.

• Dynamic IP – assigned automatically and changes over time.

MAC Address

A MAC (Media Access Control) address is a hardware identifier burned into a network interface card.

• 48-bit physical address.

• Used at the Data Link Layer (Layer 2).

• Cannot be permanently changed (though temporary spoofing is possible).

• Devices on the same network segment identify each other by MAC.

OSI Model (7 Layers)

A conceptual framework that explains how data moves through a network.

1. Application – HTTP, FTP, SMTP

2. Presentation – Encryption, compression (SSL/TLS)

3. Session – Connections, sessions

4. Transport – TCP (reliable), UDP (fast, connectionless)

5. Network – IP, ICMP

6. Data Link – Ethernet, MAC addresses, ARP

7. Physical – Cables, signals, hardware

TCP/IP Model (4 Layers)

The real-world model used on the internet.

1. Application – HTTP, DNS, SMTP

2. Transport – TCP, UDP

3. Internet – IPv4, IPv6, ICMP

4. Network Interface – Ethernet, Wi-Fi, Frame Relay

Core Networking Services

DNS (Domain Name System)

Translates domain names (google.com) into IP addresses.

DHCP (Dynamic Host Configuration Protocol)

Automatically assigns IP addresses to devices.

ARP (Address Resolution Protocol)

Maps an IP address to a MAC address within a local network.

NAT (Network Address Translation)

Allows many private devices to share one public IP address.

Security & Networking Devices

VPN

Creates an encrypted tunnel so your traffic is private.

Firewall

Filters traffic to protect networks from threats.

Router

Connects different networks and directs traffic.

Switch

Connects multiple devices within a network (Layer 2).

Advanced switches (Layer 3) can also route traffic.