IPv6 Configuration Guide K/KA/KB.15.15

DNS Configuration
Up to three DNS servers can be configured. The addresses must be prioritized, and can be for
any combination of IPv4 and IPv6 DNS servers.
NOTE: This section describes the commands for configuring DNS operation for IPv6 DNS
applications. For further information and examples on using the DNS feature, see “DNS Resolver”
in appendix, “Troubleshooting”, in the current Management and Configuration Guide for your
switch.
Syntax
[no] ip dns server-address priority 1 - 3 ip-addr [ oobm ]
Used at the global config level to configure the address and priority of a DNS
server. Allows for configuring up to three servers providing DNS service. (The servers
must all be accessible to the switch.) The command allows both IPv4 and IPv6
servers in any combination and any order of priority.
priority 1 - 3
Identifies the order in which the specified DNS server will be accessed by a
DNS resolution attempt. A resolution attempt tries each configured DNS server
address, in ascending order of priority, until the attempt is successful or all
configured server options have been tried and failed. To change the priority of
an existing server option, you must remove the option from the switch
configuration and re-enter it with the new priority. If another server address is
configured for the new priority, you must also remove that address from the
configuration before re-assigning its priority to another address.
The no form of the command removes the specified address from the server
address list configured on the switch.
ip-addr
Specifies the address of an IPv6 or IPv4 DNS server.
oobm
For switches that have a separate out-of-band management (OOBM) port, this
parameter specifies that communication with the DNS server goes through that
OOBM port.
Syntax
[no] ip dns domain-name domain-name-suffix
Used at the global config level to configure the domain suffix that is automatically
appended to the host name entered with a command supporting DNS operation.
Configuring the domain suffix is optional if you plan to use fully qualified domain
names in all cases instead of just entering host names.
You can configure up to three addresses for DNS servers in the same or different
domains. However, you can configure only one domain name suffix. This means
that a fully qualified domain name must be used to resolve addresses for hosts that
do not reside in the same domain as the one you configure with this command.
That is, if the domain name suffix and the address of a DNS server for that same
domain are both configured on the switch, then you need to enter only the host
name of the desired target when executing a command that supports DNS operation.
But if the DNS server used to resolve the host name for the desired target is in a
different domain than the domain configured with this command, then you need to
enter the fully qualified domain name for the target.
The no form of the command removes the configured domain name suffix.
282 IPv6 Diagnostic and Troubleshooting