IPv6 Addresses
Internet Protocol version 6 addressing fundamentals - Complete guide to IPv6 addresses, structure, types, and configuration.
About IPv6 Addresses
IPv6 (Internet Protocol version 6) is the latest version of the Internet Protocol, designed to replace IPv4.
- 128-bit addresses written in hexadecimal notation (e.g., 2001:db8::1)
- Provides 340 undecillion unique addresses (3.4 × 10³⁸)
- Features built-in security, auto-configuration, and improved routing
IPv6 Address Structure
Full Format
2001:0db8:85a3:0000:0000:8a2e:0370:73348 groups of 4 hexadecimal digits
Compressed Format
2001:db8:85a3::8a2e:370:7334Leading zeros omitted, :: represents consecutive zeros
Address Composition
Network Prefix (64 bits) + Interface ID (64 bits)
Typically /64 networks for end-user subnets
Typically /64 networks for end-user subnets
Unicast
One-to-one communication
Global: Routable on internet
Link-local: Local network only
Unique local: Private addressing
Multicast
One-to-many communication
Prefix: ff00::/8
Replaces: IPv4 broadcast
Efficient: Targeted delivery
Anycast
One-to-nearest communication
Load balancing: Automatic routing
Redundancy: Failover support
Services: DNS, CDN optimization
IPv6 Address Ranges & Special Addresses
| Address Range | Prefix | Type | Purpose | Scope |
|---|---|---|---|---|
| 2000::/3 | /3 | Global Unicast | Internet routable addresses | Global |
| fe80::/10 | /10 | Link-local Unicast | Local network communication | Link |
| fc00::/7 | /7 | Unique Local Unicast | Private addressing (like RFC 1918) | Organization |
| ff00::/8 | /8 | Multicast | One-to-many communication | Variable |
| ::1/128 | /128 | Loopback | Local host (like 127.0.0.1) | Node |
| ::/128 | /128 | Unspecified | No address assigned (like 0.0.0.0) | Node |
| 2001:db8::/32 | /32 | Documentation | Examples and documentation (RFC 3849) | Reserved |