IPv6 – SLAAC Stateless Address Autoconfiguration

As you will see here there are two kinds of IPv6 address autoconfiguration. One of them is the old well know way to automatically configure IP address from IPv4 world, DHCP. The other way to make the autoconfiguration in IPv6 world in new and really interesting as it leaves the host the ability to make the autoconfiguration by themselves without the need to communicate to any other system.

IPv6 is meant for various purposes but one main purpose it serves is that it makes life of the network administrators easier, especially when it comes to dealing with vast address space provided by IPv6 provides as compared to IPv4. In order to meet this need the automatic address configuration, autoconfiguration was created.

ipv6

As a result an IPv6 host can configure its complete or part of the address automatically, which depends on the type and method it uses for autoconfiguration. The method types include:

  • Stateful autoconfiguration
  • Stateless autoconfiguration using EUI-64 addressing process (SLAAC)

Stateful autoconfiguration is a method in which a host or router is assigned its entire 128-bit IPv6 address with the help of DHCP.

Stateless autoconfiguration or SLAAC is another method in which the host or router interface is assigned a 64-bit prefix, and then the last 64 bits of its address are derived by the host or router with help of EUI-64 process. This process in fairly simple but there is another article on this site on this link that will make it easier to understand so here we will skip this part. SLAAC uses NDP protocol to work and NDP is another thing that I have written an article earlier so you can read more about NDP here.

After all those article that you have here to read it will hopefully be clear how this technology enables all host on the IPv6 network to have their own globally unique IPv6 address without the need for having someone else configure it for him. If you think that there is no better way to do things but to du it yourself then you will be convinced that there is no better way of configure the IP address on host but to give him the ability to do it by himself. There will be no other servers, routers or anything else that can fail and leave the host without the address. From my perspective this is the reason that SLAAC technology is brilliant.

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