Figure 52. NDP Router RedirectIPv6 Neighbor Discovery of MTU PacketsYou can set the MTU advertised through the RA packets to incoming routers, without altering the actualMTU setting on the interface.The ipv6 nd mtu command sets the value advertised to routers. It does not set the actual MTU rate. Forexample, if you set ipv6 nd mtu to 1280, the interface still passes 1500-byte packets, if that is what isset with the mtu command.Configuring the IPv6 Recursive DNS ServerYou can configure up to four Recursive DNS Server (RDNSS) addresses to be distributed via IPv6 routeradvertisements to an IPv6 device, using the ipv6 nd dns-server ipv6-RDNSS-address {lifetime| infinite} command in INTERFACE CONFIG mode.The lifetime parameter configures the amount of time the IPv6 host can use the IPv6 RDNSS address forname resolution. The lifetime range is 0 to 4294967295 seconds. When the maximum lifetime value,4294967295, or the infinite keyword is specified, the lifetime to use the RDNSS address does notexpire. A value of 0 indicates to the host that the RDNSS address should not be used. You must specify alifetime using the lifetime or infinite parameter.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.448 IPv6 Routing
