The Internet Protocol (IP) is the foundation of all internet applications. Other protocols, such as TCP and UDP, build upon it, transporting services like HTTP(S), email, telephony, and DNS. IPv6 is replacing the outdated transport protocol IPv4 because its relatively small address space of around 4 billion addresses has long been exhausted. IPv6 is now almost ubiquitous and more useful than many realize.
Even if you don't run a home cloud, you should enable it in your router. NAT in the router only masks the problem by hiding multiple devices behind a single public IPv4 address. IPv6 expands the address space to a massive 340 sextillion, which should be sufficient for the foreseeable future, even with multiple addresses per device. Furthermore, this will make the network more compatible in the long run, as more and more providers and services prefer IPv6.
This means the internet functions as it was originally intended: In principle, every host can directly reach every other host, provided firewalls along the way allow it. Since older devices often only understand IPv4, both protocols will continue to run in parallel in dual-stack mode in many places for a long time to come. IPv4 hasn't been able to do everything for a long time: This outdated technology only barely masks the address shortage through NAT.
Users whose network is connected to the internet via cable TV often cannot access their home cloud from outside or establish a VPN connection because their router doesn't receive a public IPv4 address. This is possible with IPv6 networks, and there are further advantages: multiple servers on the LAN can offer the same services simultaneously, or administrators can remotely manage any host on the LAN via remote desktop.
As with IPv4, IPv6 also has addresses that are only valid within the network, within the prefix. fe80::/10. Then a computer has at least one globally valid IPv6 address (Globally Unique Address, GUA) through which it can reach IPv6 servers on the internet. Finally, many routers optionally offer Unique Local Addresses (ULAs, range). fd00::/8) on. These allow companies to route traffic between departments, even if they do not have internet access.
The prefix is the first part of the IPv6 address, assigned by the provider. The router uses it to decide whether a packet should go to the provider, another router on the network, or the local (W)LAN. The second half of the address is the device identifier (IID) on the local network. Many providers assign larger prefixes, such as... /56, This allows for the operation of 256 separate subnets: 56 bits to the Internet, eight subnet bits and 64 bits within the subnet for the hosts.
Each host is allowed to assign itself IPv6 addresses using the prefix specified by the router. This helps to obscure user behavior using Privacy Extensions: The computer regularly appends a new random host part to the subnet prefix and uses this address for new connections. In contrast, the computer uses IPv6 addresses with a constant host part for unsolicited incoming traffic, such as for server functions or remote control. .
Long IPv6 addresses can be shortened: Leading zeros in a block of four digits can be omitted, and exactly one continuous string of zeros can be replaced by two colons. 2001:0db8:0000:0042:0000:0000:0000:0001 is first achieved by removing the leading zeros in each block of four 2001:db8:0:42:0:0:0:1.
The longest continuous zero section can then be considered to be... :: move together, that will become 2001:db8:0:42::1. An even clearer example: fe80:0000:0000:0000:02aa:00ff:fe28:9c5a will be fe80::2aa:ff:fe28:9c5a. This is important: :: It may only be used once per address. Otherwise, it would later be unclear how many. 0000-blocks were actually meant.
Ultimately, IPv6 is less complicated than it first appears. Even those who don't run a home cloud should enable it in their router. With the right addresses and properly configured firewalls, IPv6 works in the background and makes network operations significantly easier. Enabling IPv6 today not only prepares your network for tomorrow's applications but also gives you back freedom, simplicity, and control right now.