Address Privacy
The privacy of autoconfigured IPv6 addresses using the interface identifier is a major issue in the IETF. If an IPv6 address is built using the MAC identifier, your Internet access could be traced because this identifier is unique to your interface. Part of the concern is the result of a misunderstanding. An IPv6 node can have an address based on the interface identifier, but this is not a requirement. As an alternative, the IPv6 device can have an address like the ones currently used with IPv4, static and manually configured or dynamically assigned by a DHCP server. In early 2001, RFC 3041, “Privacy Extensions for Stateless Address Autoconfiguration in IPv6,” was published; it introduces a new kind of address, available only in IPv6, that contains a random number in place of the factory-assigned serial number. This address can also change over time. An Internet device that is a target for IP communication—for instance, a web or FTP server—needs a unique and stable IP address. But a host running a browser or an FTP client does not need to have the same address every time it connects to the Internet. With the address architecture in IPv6, you can choose between two types of addresses:
- Unique stable IP addresses
Assigned through manual configuration, a DHCP server, or autoconfiguration using the interface identifier
- Temporary transient IP addresses
Assigned using a random number in place of the interface identifier
Link- and Site-Local Addresses
With IPv4, organizations ...