Stateless Address AutoConfiguration (SLAAC) is method by which hosts attached to an IPv6 network can obtain a global address through communication with a router. In SLAAC, the host sends a router solicitation, message. If an IPv6 router is present, it replies with its IPv6 prefix. The host combines this prefix with its 64-bit EUI-64 address (typically a MAC address) to create a globally routable IPv6 host address.
See: RFC 4862.
Reference: