An IPv6 device is automatically assigned a link-local address, which is a type of address that is used for communication within a local network segment. This address is generated using the device's MAC address and the prefix "FE80::/10". Link-local addresses are essential for functions such as neighbor discovery and are not routable beyond the local link.
At a minimum, IPv6-enabled interfaces require a link-local address, which is automatically generated and has the prefix fe80::/10. This address is used for communication within the local network segment and is essential for routing protocols and neighbor discovery. In addition, while link-local addresses are mandatory, globally routable addresses are typically assigned for broader network communication.
Globally routable and reachable IPv6 addresses are known as global unicast addresses. These addresses fall within the range of 2000::/3 and are assigned by the Internet Assigned Numbers Authority (IANA) to ensure unique identification across the Internet. They are used for direct communication over the Internet and can be routed by routers worldwide.
When we talk of global unicast addresses, we mean an address with global scope. That is, an address that is globally unique and can therefore be routed globally with no modification.
Teredo
format prefix
IPv6 addresses that begin with 2000 are known as global unicast addresses. These addresses are routable on the internet and are used for identifying individual interfaces on devices that require unique addresses. They are similar to public IPv4 addresses and can be assigned to devices for direct communication over the internet.
To find a specific type of address in IPv6, you can refer to the address structure and prefix. IPv6 addresses are categorized into various types, such as global unicast, link-local, multicast, and anycast, each with distinct prefixes. For example, link-local addresses start with "FE80::/10," while multicast addresses start with "FF00::/8." You can use network tools or commands like ping, traceroute, or specific IPv6 address lookup tools to identify and verify the type of address in use.
A dynamic address, assigned by the DHCP server. Static addresses can also be assigned by the DHCP server through reservations using the unique MAC addresses to identify each machine. This ensures a machine receives the same address each time it requests an address from the server.
The IPv6 address that is required for other computers on a local network to communicate with each other is, the "Link-local address". The first hextet will always begin with FE80.
IPv6 is not a separate Internet. It is a separate type of address. Machines can have both IPv4 and IPv6 addresses simultaneously. Many web servers already do this, and nearly all of the Internet's backbone routers have both types of address. Theoretically, if you are using IPv4 or IPv6, your data will take the same path, across the same hardware, to its destination. However, you may not be able to get an IPv6 address from your Internet Service Provider, perhaps since they are not yet IPv6-ready (often the case with smaller ISPs). In this case, you can setup a 6-to-4 tunnel which connects your IPv6 network inside your home to the IPv4 network of your ISP. Presumably, that ISP will also have a 4-to-6 tunnel allowing your packets to make their way to the IPv6 destination. That being said, if you know the IPv4 address of the same server, you can just use that without the need for IPv6. Only in the rare cases where servers only have an IPv6 address do you need to ensure that your packets come from an IPv6 address, then travel to the destination somehow (directly across an IPv6 network, or using tunnels as described above).
Unique local unicast address also called unique local address (ULA)
Unique local unicast address also called unique local address (ULA)