The DNS server address does not allow the following:• link local addresses• loopback addresses• prefix addresses• multicast addresses• invalid host addressesIf you specify this information in the IPv6 RDNSS configuration, a DNS error is displayed.Example for Configuring an IPv6 Recursive DNS ServerThe following example configures a RDNNS server with an IPv6 address of 1000::1 and a lifetime of 1second.Dell(conf-if-te-1/1)#ipv6 nd dns-server ?X:X:X:X::X Recursive DNS Server's (RDNSS) IPv6 addressDell(conf-if-te-1/1)#ipv6 nd dns-server 1000::1 ?<0-4294967295> Max lifetime (sec) which RDNSS address may be used forname resolutioninfinite Infinite lifetime (sec) which RDNSS address may be usedfor name resolutionDell(conf-if-te-1/1)#ipv6 nd dns-server 1000::1 1Debugging IPv6 RDNSS Information Sent to the HostTo verify that the IPv6 RDNSS information sent to the host is configured correctly, use the debug ipv6nd command in EXEC Privilege mode.Example of Debugging IPv6 RDNSS Information Sent to the HostThe following example debugs IPv6 RDNSS information sent to the host.Dell(conf-if-te-1/1)#do debug ipv6 nd tengigabitethernet 1/1ICMPv6 Neighbor Discovery packet debugging is on for tengigabitethernet 1/1Dell(conf-if-te-1/1)#00:13:02 : : cp-ICMPV6-ND: Sending RA on Te 1/1current hop limit=64, flags: M-, O-,router lifetime=1800 sec, reachable time=0 ms, retransmit time=0 msSLLA=00:01:e8:8b:75:70prefix=1212::/64 on-link autoconfigvalid lifetime=2592000 sec, preferred lifetime=604800 secdns-server=1000::0001, lifetime=1 secdns-server=3000::0001, lifetime=1 secdns-server=2000::0001, lifetime=0 secThe last 3 lines indicate that the IPv6 RDNSS information was configured correctly.dns-server=1000::0001, lifetime=1 secdns-server=3000::0001, lifetime=1 secdns-server=2000::0001, lifetime=0 secIf the DNS server information is not displayed, verify that the IPv6 recursive DNS server configuration wasconfigured on the correct interface.390 IPv6 Routing
