Configuring IPv6 DNS· 1

Overview·· 1

Configuring the IPv6 DNS client 1

Configuring static domain name resolution· 1

Configuring dynamic domain name resolution· 1

Displaying and maintaining IPv6 DNS· 2

IPv6 DNS configuration examples 2

Static domain name resolution configuration example· 3

Dynamic domain name resolution configuration example· 3

 

The term "router" in this document refers to both routers and Layer 3 switches.

Overview

IPv6 DNS is responsible for translating domain names into IPv6 addresses. Like IPv4 DNS, IPv6 DNS includes static domain name resolution and dynamic domain name resolution. The functions and implementations of the two types of domain name resolution are the same as those of IPv4 DNS. For more information, see "Configuring IPv4 DNS."

Configuring the IPv6 DNS client

Configuring static domain name resolution

Configuring static domain name resolution refers to specifying the mappings between host names and IPv6 addresses. Static domain name resolution allows applications such as Telnet to contact hosts by using host names instead of IPv6 addresses.

Follow these guidelines when you configure static domain name resolution:

·     A host name can be mapped to one IPv6 address only. If you map a host name to different IPv6 addresses, the last configuration takes effect.

·     You can configure up to 50 mappings between domain name and IPv6 address on the switch.

To configure static domain name resolution:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Configure a mapping between a host name and an IPv6 address.	ipv6 host hostname ipv6-address	Not configured by default.

 

Configuring dynamic domain name resolution

To send DNS queries to a correct server for resolution, dynamic domain name resolution needs to be enabled and a DNS server needs to be configured.

In addition, you can configure a DNS suffix that the system will automatically add to the provided domain name for resolution.

Follow these guidelines when you configure dynamic domain name resolution:

·     You can configure up to six DNS servers, including those with IPv4 addresses on a switch.

·     You can specify up to ten DNS suffixes on a switch.

To configure dynamic domain name resolution:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enable dynamic domain name resolution.	dns resolve	Disabled by default. For more information about the dns resolve command, see Layer 3—IP Services Command Reference.
3.     Specify a DNS server.	dns server ipv6 ipv6-address [ interface-type interface-number ]	Not specified by default. If the IPv6 address of a DNS server is a link-local address, you need to specify the interface-type and interface-number arguments.
4.     Configure a DNS suffix.	dns domain domain-name	Not configured by default. Only the provided domain name is resolved. For more information about the dns domain command, see Layer 3—IP Services Command Reference.

 

Displaying and maintaining IPv6 DNS

Task	Command	Remarks
Display the static IPv6 domain name resolution table.	display ipv6 host [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display IPv6 DNS server information.	display dns ipv6 server [ dynamic ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display DNS suffixes.	display dns domain [ dynamic ] [ | { begin | exclude | include } regular-expression ]	Available in any view.
Display information about dynamic IPv6 domain name cache.	display dns host ipv6 [ | { begin | exclude | include } regular-expression ]	Available in any view.
Clear information about dynamic IPv6 domain name cache.	reset dns host ipv6	Available in user view.

 

For more information about the display dns domain, display dns host ipv6, and reset dns host ipv6 commands, see Layer 3—IP Services Command Reference.

IPv6 DNS configuration examples

IMPORTANT: By default, Ethernet, VLAN, and aggregate interfaces are down. To configure such an interface, bring the interface up by executing the undo shutdown command.

 

Static domain name resolution configuration example

Network requirements

As shown in Figure 1, the device wants to access the host by using an easy-to-remember domain name rather than an IPv6 address. Configure static domain name resolution on the device so that the device can use the domain name host.com to access the host whose IPv6 address is 1::2.

Figure 1 Network diagram

 

Configuration procedure

# Configure a mapping between host name host.com and IPv6 address 1::2.

<Device> system-view

[Device] ipv6 host host.com 1::2

# Enable IPv6.

[Device] ipv6

# Use the ping ipv6 host.com command to verify that the device can use static domain name resolution to get IPv6 address 1::2 corresponding to host.com.

[Device] ping ipv6 host.com

  PING host.com (1::2):

  56  data bytes, press CTRL_C to break

    Reply from 1::2

    bytes=56 Sequence=1 hop limit=128  time = 3 ms

    Reply from 1::2

    bytes=56 Sequence=2 hop limit=128  time = 1 ms

    Reply from 1::2

    bytes=56 Sequence=3 hop limit=128  time = 1 ms

    Reply from 1::2

    bytes=56 Sequence=4 hop limit=128  time = 2 ms

    Reply from 1::2

    bytes=56 Sequence=5 hop limit=128  time = 2 ms

  --- host.com ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 1/1/3 ms

Dynamic domain name resolution configuration example

Network requirements

As shown in Figure 2, the device wants to access the host by using an easy-to-remember domain name rather than an IPv6 address. The IPv6 address of the DNS server is 2::2/64 and the server has a com domain, which stores the mapping between domain name host and IPv6 address 1::1/64.

Configure dynamic domain name resolution and the domain name suffix com on the device that serves as a DNS client so that the device can use domain name host to access the host with the domain name host.com and the IPv6 address 1::1/64.

Figure 2 Network diagram

 

Configuration procedure

Before performing the following configuration, make sure the device and the host are accessible to each another through available routes, and the IPv6 addresses of the interfaces are configured as shown in Figure 2.

This configuration might vary with different DNS servers. The following configuration is performed on a PC running Windows server 2003. Make sure the DNS server supports the IPv6 DNS function so that the server can process IPv6 DNS packets, and the interfaces of the DNS server can forward IPv6 packets.

1.     Configure the DNS server:

a.     Select Start > Programs > Administrative Tools > DNS.

The DNS server configuration page appears, as shown in Figure 3.

b.     Right-click Forward Lookup Zones, select New Zone, and then follow the instructions to create a new zone named com.

Figure 3 Creating a zone

 

c.     On the DNS configuration page, right-click zone com, and select Other New Records.

Figure 4 Creating a record

 

d.     On the page that appears, select IPv6 Host (AAAA) as the resource record type.

e.     Click Create Record.

Figure 5 Selecting the resource record type

 

f.     On the page appears, enter host name host and IPv6 address 1::1, and then click OK.

The mapping between the host name and the IPv6 address is created.

Figure 6 Adding a mapping between domain name and IPv6 address

 

2.     Configure the DNS client:

# Enable dynamic domain name resolution.

<Device> system-view

[Device] dns resolve

# Specify the DNS server 2::2.

[Device] dns server ipv6 2::2

# Configure com as the DNS suffix.

[Device] dns domain com

Verifying the configuration

# Use the ping ipv6 host command on the device to verify that the communication between the device and the host is normal and that the corresponding destination IP address is 1::1.

[Device] ping ipv6 host

 Trying DNS resolve, press CTRL_C to break

 Trying DNS server (2::2)

  PING host.com (1::1):

  56  data bytes, press CTRL_C to break

    Reply from 1::1

    bytes=56 Sequence=1 hop limit=126  time = 2 ms

    Reply from 1::1

    bytes=56 Sequence=2 hop limit=126  time = 1 ms

    Reply from 1::1

    bytes=56 Sequence=3 hop limit=126  time = 1 ms

    Reply from 1::1

    bytes=56 Sequence=4 hop limit=126  time = 1 ms

    Reply from 1::1

    bytes=56 Sequence=5 hop limit=126  time = 1 ms

 

  --- host.com ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 1/1/2 ms