IPv6 is gaining traction and is starting to be deployed rapidly. Adding fuel to this fire is advancements in AI / ML , AR / VR, financial markets and other technologies. Below is accurate and exhaustive list of different types of IPv6 addresses and its use
- Global Unicast
- Globally unique public IPv6 addresses usable over the internet.
- Here are the Global Unicast IPv6 address assignments
- Unique local
- Private IPv6 addresses not usable over the internet (ISP will drop packets)
- Link local
- Automatically generated IPv6 address when the network interface is enabled with IPv6 support.
- Address starts with FE8 and then interface ID is generated using EUI-64
- Used for communication within a subnet like OSPF LSAs, next hop for static routes and NDP
- Anycast
- Any global unicast or unique local IPv6 address can be designated as Anycast address
- Multicast
- Address block FF00::/8 used for multicast in IPv6
- Multicast address scopes
- Interface-local
- Link-local
- Site-local
- Organization-local
- Global
- EUI64
- EUI = Extended Unique Identifier. This method allows automatic generation of IPv6 address using MAC address
- EUI-64 is a method of converting a 48bit MAC address into 64 bit interface identifier
- Divide MAC address at the midpoint — e.g 1234 5678 90AB can be divided in to 123456 | 7890AB
- Insert FFFE in middle — 1234 56FF FE78 90AB
- Invert the 7th bit from the most significant side — 1234 56FF FE78 90AB becomes 1034 56FF FE78 90AB
- This 64 bit interface identifier is then used as host portion of a /64 IPv6 address by adding it on to the 64 bit network prefix making a 128bit IPv6 address
- :: (two colons)
- Same as IPv4 0.0.0.0
- ::1. (loopback)
- Same as IPv4 127.0.0.0/8 address range. IPv6 only uses a single address for loopback unlike IPv4
