IPv6 Addressing – Class Notes

1. What Is IPv6?

IPv6 (Internet Protocol version 6) is the newest version of the Internet Protocol. It was created to replace IPv4 and solve the problem of running out of IP addresses.

• IPv4 uses 32-bit addresses (about 4.3 billion total)
• IPv6 uses 128-bit addresses (about 340 undecillion addresses)

IPv6 allows every device—computers, phones, servers, and IoT devices—to have a unique address.

2. Why IPv6 Is Needed

• Much larger address space
• No need for NAT (Network Address Translation)
• Better support for modern networks and IoT
• Improved efficiency and scalability

3. IPv6 Address Format

• Written in hexadecimal (0–9, A–F)
• Made up of 8 groups of 16 bits
• Groups are separated by colons (:)

Each group is called a hextet.

4. IPv6 Address Simplification Rules

Rule 1: Remove Leading Zeros

Rule 2: Double Colon (::)

• Replaces one continuous group of zeros
• Can only be used once per address

5. Types of IPv6 Addresses

Unicast

• Identifies one device
• Most common type

Multicast

• Sends traffic to multiple devices
• Replaces IPv4 broadcast
• Starts with FF00::/8

Anycast

• Assigned to multiple devices
• Traffic goes to the closest device

6. Common IPv6 Address Types

7. Link-Local Addresses

• Automatically assigned
• Used only on the local network
• Not routable on the Internet
• Always start with FE80::

8. IPv6 vs IPv4

9. IPv6 and Security

• Supports IPsec by design
• Security depends on configuration and firewalls
• IPv6 is not automatically secure

10. Key Takeaways