How does an IPv6 client ensure that it has a unique address after it configures its IPv6 address using the SLAAC allocation method?
- It sends an ARP message with the IPv6 address as the destination IPv6 address.
- It checks with the IPv6 address database that is hosted by the SLAAC server.
- It contacts the DHCPv6 server via a special formed ICMPv6 message.
- It sends an ICMPv6 Neighbor Solicitation message with the IPv6 address as the target IPv6 address.*
SLAAC is a stateless allocation method and does not use a DHCP server to manage the IPv6 addresses. When a host generates an IPv6 address, it must verify that it is unique. The host will send an ICMPv6 Neighbor Solicitation message with its own IPv6 address as the target. As long as no other device responds with a Neighbor Advertisement message, then the address is unique.