Configuring The Ipv6 Recursive Dns Server; Debugging Ipv6 Rdnss Information Sent To The Host - Dell S4820T Configuration Manual

Configuring the IPv6 Recursive DNS Server

You can configure up to four Recursive DNS Server (RDNSS) addresses to be distributed via IPv6 router
advertisements 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 for
name 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 not
expire. A value of 0 indicates to the host that the RDNSS address should not be used. You must specify a
lifetime 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 addresses
If you specify this information in the IPv6 RDNSS configuration, a DNS error is displayed.
Example for Configuring an IPv6 Recursive DNS Server
The following example configures a RDNNS server with an IPv6 address of 1000::1 and a lifetime of 1
second.
Dell(conf-if-te-1/1)#ipv6 nd dns-server ?
X:X:X:X::X
Dell(conf-if-te-1/1)#ipv6 nd dns-server 1000::1 ?
<0-4294967295>
name resolution
infinite
for name resolution
Dell(conf-if-te-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 configured 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-te-1/1)#do debug ipv6 nd tengigabitethernet 1/1
ICMPv6 Neighbor Discovery packet debugging is on for tengigabitethernet 1/1
Dell(conf-if-te-1/1)#00:13:02 : : cp-ICMPV6-ND: Sending RA on Te 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
510
Recursive DNS Server's (RDNSS) IPv6 address
Max lifetime (sec) which RDNSS address may be used for
Infinite lifetime (sec) which RDNSS address may be used
IPv6 Routing