The IPv6 address is 128 bits long, being separated into 8 groups of 4 hexadecimal characters. In addition, IPv6 is logically divided into two 64-bit parts, the first for the network prefix and the second for interface identification.
An IPv6 address can be of three specific types:
- Unicast: For a single device, packet traffic occurs via the shortest route to the device;
- Multicast: Refers to a grouping of devices, when the data packet is sent to the recipient, each member of the group receives a copy of the packet;
- Anycast: Refers to a grouping of devices that have the same prefix, the data packet is only delivered to the nearest sender.
One of the main differences between IPv6 and IPv4 is the multiple extension headers, generating greater efficiency thanks to the possibility to adjust their size, in addition to being able to add new headers in order to meet new needs. There are six types of predefined extension header, they are:
- Destination Options;
- Encrypted security payload.
A host generally has two types of IPv6 unicast: the Local Link Address and the Global Unicast Address. A global address can be obtained using the following auto-configuration methods:
- SLAAC: It means Stateless Address Auto Configuration, through this method the host uses the Router Advertising prefix to generate two Unicast Global Addresses. In this method the interface ID is unique on the local network thanks to the use of the MAC address or a random value;
- Stateless DHCPv6: Through this method, the host uses the Router Advertising prefix to generate two Global Unicast Addresses and uses any available DHCPv6 server to obtain information relevant to the configuration, for example DNS, Gateway and NTP;
- Stateful DHCPv6: In this method, the host is unable to obtain the prefix through Router Advertising, in order to mitigate this, a broadcast is made requesting the Global Unicast Address and any other necessary configuration of an available DHCPv6 server;
- Stateful DHCPv6 and SLAAC combined: In this alternative, simply apply the first and penultimate method simultaneously.
In the system, it is possible to enable and configure IPv6, define how Router Advertising will be carried out and perform the conversion from IPv4 to IPv6 through IP mapping.
To make these settings, click on the IPv6 Settings tab, as shown below:
IPv6 Settings tab
The following screen will appear:
This screen consists of the following panels:
Next, we will analyze each panel in detail.