Administrator Guide

The DNS server address does not allow the following:
• link local addresses
• loopback addresses
• prex addresses
• multicast addresses
• invalid host addresses
If you specify this information in the IPv6 RDNSS conguration, a DNS error is displayed.
Example for Conguring an IPv6 Recursive DNS Server
The following example congures a RDNNS server with an IPv6 address of 1000::1 and a lifetime of 1 second.
Dell(conf-if-gi-1/1)#ipv6 nd dns-server ?
X:X:X:X::X Recursive DNS Server's (RDNSS) IPv6 address
Dell(conf-if-gi-1/1)#ipv6 nd dns-server 1000::1 ?
<0-4294967295> Max lifetime (sec) which RDNSS address may be used for name resolution
infinite Infinite lifetime (sec) which RDNSS address may be used for name resolution
Dell(conf-if-gi-1/1)#ipv6 nd dns-server 1000::1 1
Debugging IPv6 RDNSS Information Sent to the Host
To verify that the IPv6 RDNSS information sent to the host is congured correctly, use the debug ipv6 nd command in EXEC Privilege
mode.
Example of Debugging IPv6 RDNSS Information Sent to the Host
The following example debugs IPv6 RDNSS information sent to the host.
Dell(conf-if-gi-1/1)#do debug ipv6 nd gigabitethernet 1/1
ICMPv6 Neighbor Discovery packet debugging is on for gigabitethernet 1/1
Dell(conf-if-gi-1/1)#00:13:02 : : cp-ICMPV6-ND: Sending RA on Gi 1/1
current hop limit=64, flags: M-, O-,
router lifetime=1800 sec, reachable time=0 ms, retransmit time=0 ms
SLLA=00:01:e8:8b:75:70
prefix=1212::/64 on-link autoconfig
valid lifetime=2592000 sec, preferred lifetime=604800 sec
dns-server=1000::0001, lifetime=1 sec
dns-server=3000::0001, lifetime=1 sec
dns-server=2000::0001, lifetime=0 sec
The last 3 lines indicate that the IPv6 RDNSS information was congured correctly.
dns-server=1000::0001, lifetime=1 sec
dns-server=3000::0001, lifetime=1 sec
dns-server=2000::0001, lifetime=0 sec
If the DNS server information is not displayed, verify that the IPv6 recursive DNS server conguration was congured on the correct
interface.
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IPv6 Routing