Cybersecurity Foundations (Grades 6–8) · lesson 14 of 48 · 12 min
Every Device Has an Address
When you send a letter, it needs a destination address. When data travels across the internet, it works the same way — every device needs an address so data knows where to go. That address is called an IP address (Internet Protocol address).
An IP address is a numerical label assigned to every device connected to a network. It serves two purposes: identifying the device (who you are) and locating it on the network (where you are). Without IP addresses, the internet could not route data from one place to another.
Understanding IP addresses matters for cybersecurity because attackers use IP addresses to target systems, investigators use them to trace attacks, and privacy tools like VPNs work by masking your real IP address.
How many IP addresses exist?
IPv4 provides about 4.3 billion addresses — which seemed like plenty in 1983. By the 2010s, we were running out. IPv6 was created to solve this: it provides 340 undecillion addresses (340 followed by 36 zeros). That is enough to give every atom on Earth’s surface its own IP address, with addresses to spare.
IPv4 vs. IPv6
There are two versions of IP addresses in use today.
Most of the internet still runs on IPv4, but IPv6 adoption is growing. Your device likely has both — a process called dual-stack. When you visit a website, your device and the server negotiate which version to use.
Public vs. Private IP Addresses
Not all IP addresses are the same. There is an important distinction between public and private addresses that affects both how the internet works and your privacy.
Here is how it works: your home router has one public IP address assigned by your ISP. All devices in your home (phone, laptop, smart TV) get private IP addresses from your router. When any device sends data to the internet, the router translates the private address to the public address — a process called NAT (Network Address Translation). The website you visit sees your router’s public IP, not your individual device’s private IP.
This matters for privacy: your public IP address can be used to approximately locate you (city level), identify your ISP, and track your activity across websites. A VPN replaces your public IP with the VPN server’s IP, masking your real location and identity.
Activity 1 — IP Address Concepts Matching
IP Address Concepts
Static vs. Dynamic IP Addresses
IP addresses can be either static (fixed) or dynamic (changing).
Most home internet users have dynamic public IP addresses — your ISP assigns you a new one periodically. This provides a small privacy benefit. Web servers need static IPs so users can always find them at the same address.
IP addresses and privacy
Your public IP address is logged by every website you visit. It can be used to approximately identify your city and ISP. Law enforcement can subpoena your ISP to get your identity from your IP address. This is how many cybercriminals are caught — and why sophisticated attackers use VPNs, Tor, or compromised machines to hide their real IP.
Activity 2 — IP Address Scenario Analysis
IP Address Scenarios
Activity 3 — Sort the IP Address Facts
True or False: IP Address Facts
IPv6 was created because IPv4 ran out of addresses. true IPv4’s ~4.3 billion addresses were exhausted. IPv6 provides 340 undecillion addresses. Your private IP address is visible to websites you visit. false NAT translates your private IP to your router’s public IP. Websites see the public IP, not your device’s private IP. A VPN masks your real public IP address from websites you visit. true A VPN routes your traffic through a VPN server. Websites see the VPN server’s IP, not your real public IP. An IP address uniquely identifies a specific person. false An IP address identifies a connection or device, not a person. Multiple people may share one IP via NAT. DHCP automatically assigns IP addresses to devices on a network. true DHCP (Dynamic Host Configuration Protocol) assigns IP addresses automatically when devices connect to a network. Static IP addresses change every time you connect to the internet. false Static IPs are fixed and never change. Dynamic IPs change periodically. Most home users have dynamic IPs.
Activity 4 — Flashcard Review
IP Addresses — Key Terms
IP Address A numerical label assigned to every device on a network. Identifies the device and its location on the network. Used to route data from source to destination across the internet.
- Core
- IPv4
Internet Protocol version 4. Format: four numbers 0-255 separated by dots (e.g. 192.168.1.1). Provides ~4.3 billion addresses — now exhausted. Still the most widely used version.
- Version
- IPv6
Internet Protocol version 6. Format: eight groups of hexadecimal digits (e.g. 2001:0db8::1). Provides 340 undecillion addresses. Created to replace IPv4. Gradually being deployed worldwide.
- Version
- Public IP Address
Your address on the internet — assigned by your ISP and visible to websites and services you connect to. Logged by every website you visit. Can be used to approximately locate you.
- Type
- Private IP Address
Your address on your local network (home, school). Not visible on the internet. Assigned by your router via DHCP. Common ranges: 192.168.x.x, 10.x.x.x.
- Type
- NAT (Network Address Translation)
A router function that translates private IP addresses to one public IP address for internet access. Allows many devices to share one public IP. Hides individual device addresses from the internet.
- Concept
- DHCP
Dynamic Host Configuration Protocol. Automatically assigns IP addresses to devices when they connect to a network. Your router uses DHCP to give your phone, laptop, and other devices their private IP addresses. Protocol
Activity 5 — IP Address Scenarios
IP Address Real-World Scenarios
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