DNS resolver for IPv6

The Domain Name System (DNS) resolver is designed for local network domains where it enables use of a host name or fully qualified domain name to support DNS-compatible commands from the switch. Beginning with software release K.13.01, DNS operation supports these features:

dual-stack operation: IPv6 and IPv4 DNS resolution
DNS-compatible commands: ping, ping6, traceroute, and traceroute6
multiple, prioritized DNS servers (IPv4 and IPv6)

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.

For example, suppose you want to configure the following on the switch:

the address 2001:db8::127:10 which identifies a DNS server in the domain named mygroup.hpnetworking.net
a priority of 1 for the above server
the domain suffix mygroup.hpnetworking.net

Assume that the above, configured DNS server supports an IPv6 device having a host name of “mars-1” (and an IPv6 address of fe80::215:60ff:fe7a:adc0) in the “mygroup.hpnetworking.net” domain. In this case you can use the device's host name alone to ping the device because the mygroup.hpnetworking.net domain has been configured as the domain name on the switch and the address of a DNS server residing in that domain is also configured on the switch. The commands for these steps are as follows:

Configuring for a Local DNS server and pinging a registered device

HP Switch(config)# ip dns server priority 1 2001:db8::127:10
HP Switch(config)# ip dns domain-name mygroup.hpnetworking.net
HP Switch(config)# ping6 mars-1
fe80::215:60ff:fe7a:adc0 is alive, time = 1 ms

However, for the same “mars-1” device, if mygroup.hpnetworking.net was not the configured domain name, you would have to use the fully qualified domain name for the device named mars-1:

HP Switch# ping6 mars-1.mygroup.hpnetworking.net

For further information and examples on using the DNS feature, see “DNS Resolver” in the Troubleshooting appendix, in the current Management and Configuration Guide for your switch.

Viewing the current DNS configuration

Use the show ip dns command to view the current DNS server configuration.

Use the show run command to view both the current DNS server addresses and the current DNS domain name in the active configuration.


	NOTE: In software release K.13.01, DNS addressing is not configurable from a DHCPv6 server.

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