Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 08-05-2008 Installation Manual page 573

On top of this basic structure, IPv6 distinguishes between five different types of unicast
addresses:
:: (unspecified)
This address is used by the host as its source address when the interface is initialized
for the first time—when the address cannot yet be determined by other means.
::1 (loopback)
The address of the loopback device.
IPv4 Compatible Addresses
The IPv6 address is formed by the IPv4 address and a prefix consisting of 96 zero
bits. This type of compatibility address is used for tunneling (see
"Coexistence of IPv4 and IPv6"
municate with others operating in a pure IPv4 environment.
IPv4 Addresses Mapped to IPv6
This type of address specifies a pure IPv4 address in IPv6 notation.
Local Addresses
There are two address types for local use:
link-local
This type of address can only be used in the local subnetwork. Packets with a
source or target address of this type should not be routed to the Internet or
other subnetworks. These addresses contain a special prefix (fe80::/10)
and the interface ID of the network card, with the middle part consisting of
zero bytes. Addresses of this type are used during automatic configuration to
communicate with other hosts belonging to the same subnetwork.
site-local
Packets with this type of address may be routed to other subnetworks, but not
to the wider Internet—they must remain inside the organization's own network.
Such addresses are used for intranets and are an equivalent of the private address
space defined by IPv4. They contain a special prefix (fec0::/10), the inter-
face ID, and a 16 bit field specifying the subnetwork ID. Again, the rest is
filled with zero bytes.
As a completely new feature introduced with IPv6, each network interface normally
gets several IP addresses, with the advantage that several networks can be accessed
through the same interface. One of these networks can be configured completely auto-
(page 556)) to allow IPv4 and IPv6 hosts to com-
Section 30.2.3,
Basic Networking 555