IP Address
IP (Internet Protocol) Address is a device's unique address on the network. Just like your home address!
01What is IPv4?
The most commonly used IP format: 192.168.1.1
- 32-bit address (4 octets × 8 bits)
- Each octet takes values from 0-255
- Total of ~4.3 billion unique addresses
- Used since 1981
IPv4 Structure
code
192.168.1.1
│ │ │ │
│ │ │ └─ Host (0-255)
│ │ └─── Subnet (0-255)
│ └─────── Network (0-255)
└─────────── Network (0-255)
02What is IPv6?
Next generation IP protocol: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
- 128-bit address (8 groups × 16 bits)
- Each group is 4 hexadecimal characters (0-9, a-f)
- Total of 340 undecillion addresses (340 × 10³⁶)
- Defined in 1998, becoming widespread today
IPv6 Shortening Rules
code
Full: 2001:0db8:0000:0000:0000:0000:0000:0001
Short: 2001:db8::1
- Leading zeros are omitted (0db8 → db8)
- Consecutive zero groups shown as ::
03Why Transition from IPv4 to IPv6?
IPv4's Problem: Address Exhaustion
| Year | Status |
|---|---|
| 1981 | IPv4 designed, 4.3 billion addresses seemed enough |
| 2011 | IANA's last IPv4 block distributed |
| 2019 | IPv4 addresses exhausted in Europe (RIPE) |
| Today | Managing with NAT and IPv6 transition |
IPv6 Advantages
| Feature | IPv4 | IPv6 |
|---|---|---|
| Address Count | 4.3 billion | 340 undecillion |
| Address Length | 32 bits | 128 bits |
| NAT Required | Yes (mandatory) | No |
| Auto Configuration | DHCP needed | Automatic with SLAAC |
| Security | Optional IPsec | Built-in IPsec |
| Header Size | Variable | Fixed (faster) |
Real World Example
Number of internet-connected devices worldwide:
- 2010: ~5 billion
- 2025: ~75 billion (including IoT)
4.3 billion IPv4 addresses will never be enough for this many devices!
04Private IP vs Public IP
| Type | IPv4 Examples | Usage |
|---|---|---|
| Private | 10.x.x.x, 172.16-31.x.x, 192.168.x.x | Home/office internal, no internet access |
| Public | 8.8.8.8, 1.1.1.1 | Unique on the internet |
| Loopback | 127.0.0.1 (localhost) | Access to own device |
05How to Find Your IP Address?
| Operating System | Command |
|---|---|
| Windows | ipconfig |
| Mac/Linux | ip addr or ifconfig |
| Public IP | curl ifconfig.me |
06Summary
- IPv4: Common but addresses running out (32-bit)
- IPv6: Future, unlimited address capacity (128-bit)
- Transition ongoing, both work together (Dual Stack)
In the simulation below, you'll better understand the IP address concept!