Josh Gahan

There are alot of new terms and techniques that are needed to be learnt in order to get a grasp of the IPv6 principles and as promised i will go over the types of IPv6 addresses that exist. The one that doesn’t exist anymore is the broadcast. Anyway they are:

IPv6 Multicast

• First 8Bits are 1
• or FF00::/8

This works just like the IPv4 brother and is used to send traffic to a subset of devices, it also functions, at times, like a broadcast. In the new IPv6 world there is no such thing but the multicast addressing does the same thing.

Unspecified

• Devices use this IPv6 address to ask for an IPv6 address from a DHCP server
• Written as ::/128

Does as described, before a device has an IP it will use the ::/128 IP as the source and when a DHCP server responds to the request an unused IPv6 address will be assigned.

Loopback

• Performs the same functions as 127.0.0.1 does in IPv4
• ::1/128

This address is used basically to troubleshoot and test the IP stack on devices.

Link Local

• Every device will generate a link local address
• Only used to communicate on the local broadcast domain, meaning it won’t pass a router or the Layer 2 link.
• Written and identified by FE80::/10
• Link-Local address are generated using the EUI-64 rules aka Stateless Address Auto-configuration (SLAAC)

The link-local address is quite unique and as stated above it will not be used outside the broadcast domain, so without any configuration at all you should be able to connect devices on the same broadcast domain and have connectivity using the Link Local addresses. It’s a pretty cool feature of IPv6 and something to look out for too.

Global

• Can be routed via the internet and between networks
• Reachable by routers globally
• 2000::/3 – First 3Bits must be 001
• AKA Global Unicast Address

Basically this is the address that your local RIR or ISP will allocate to you to use,  without going into details you would be given a further subdivided piece of the above address space to use to connect to the internet. Once this is setup and configured you will be reachable by other routers globally.

Anycast

• Allow the use of the same IP addresse in different locations
• Function like Global IPv6 Addresses.

The Anycast feature of IPv6 can be used to allow the use of identical IPv6 addresses in different locations. The reason for this is so that you can setup servers for almost anything and the requesting host will find the destination which is closer, not just via metric but this could mean physically too.