IPv6 router advertisement options for DNS configuration

Two new options in IPv6 Router Advertisements allow IPv6 routers to advertise a list of recursive DNS Server (RDNSS) addresses and a DNS Search List (DNSSL) to IPv6 hosts. RA-based DNS configuration enables the full configuration of basic networking information for hosts without requiring DHCPv6. An IPv6 host can acquire the DNS configuration (that is, the DNS recursive server addresses and DNS Search List) for the links to which the host is connected. The host learns this DNS configuration from the same RA message that provides configuration information for the link.

DNS options are included by default in every emitted RA unless the inclusion is suppressed via CLI commands or the SNMP MIB. The suppress option can be configured either globally or for an IP interface.