Networking Basics · 4
🏠 IP Addressing
Every device needs an address — here's how they work⏱ ~3 min
📬IP addresses are like home addresses
Your home address has a street name (the network) and a house number (the specific device). '192.168.1' is like 'Main Street' — it identifies the neighborhood. '.10' is like 'House #10' — it identifies your specific device. Routers use the 'street' part to get close, then the 'house number' for the final delivery.
IPv4 — The Original (Running Out!)
- •Format: 4 numbers, each 0–255, separated by dots → 192.168.1.10
- •Each number = 8 bits = 1 octet. Total = 32 bits.
- •Maximum unique addresses: 2³² = about 4.3 billion
- •Problem: There are 8 billion people on Earth — and billions of IoT devices too.
IPv6 — The Solution
- •Format: 8 groups of 4 hex digits → 2001:0db8:85a3::8a2e:0370:7334
- •128 bits total → 2¹²⁸ addresses = 340 undecillion (340 followed by 36 zeros)
- •Every grain of sand on Earth could have trillions of IP addresses
- •Still rolling out — most of the internet runs both IPv4 and IPv6 today
Private vs Public IPs
| Type | Range | Who Sees It |
|---|---|---|
| Private | 192.168.0.0 – 192.168.255.255 | Only devices inside your home/office network |
| Private | 10.0.0.0 – 10.255.255.255 | Only inside the organization |
| Private | 172.16.0.0 – 172.31.255.255 | Only inside the organization |
| Public | Everything else | Visible on the internet — assigned by your ISP |
| Special | 127.0.0.1 (localhost) | Your own computer talking to itself |
Your home router performs NAT (Network Address Translation) — it gives every device a private IP, but shares one single public IP with the entire internet. It's like an apartment building: one street address, many apartments inside.
★ FactIANA (Internet Assigned Numbers Authority) ran out of IPv4 addresses in 2011. But because of NAT, billions of devices can share a small pool of public IPs. This is why we haven't fully collapsed yet — but IPv6 adoption is accelerating fast.
🔒 SecurityIP spoofing is when an attacker fakes their source IP address to hide their identity or trick a target into trusting them. This is used in DDoS reflection attacks — send a request pretending to be the victim, get huge responses flooding back at them.
🧠Quick Checkfirst try = +5 XP
Your device shows IP 10.0.0.45. A friend's phone shows 10.0.0.46. What IP does a website see when you visit it?
🎮 Practice what you learned
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