Configuring IPv6 DNS· 2

Introduction to IPv6 DNS· 2

Configuring the IPv6 DNS client 2

Configuring static domain name resolution· 2

Configuring dynamic domain name resolution· 2

Displaying and maintaining IPv6 DNS· 3

IPv6 DNS configuration examples 3

Static domain name resolution configuration example· 4

Dynamic domain name resolution configuration example· 4

 

 

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

 

Introduction to IPv6 DNS

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 the chapter “IPv4 DNS configuration.”

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.

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

 

NOTE: ·       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.

 

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.

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.
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.

 

NOTE: ·       For more information about the dns resolve and dns domain commands, see Layer 3—IP Services Command Reference. ·       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.

 

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 the information of dynamic IPv6 domain name cache.	display dns host ipv6 [ | { begin | exclude | include } regular-expression ]	Available in any view
Clear the information of dynamic IPv6 domain name cache.	reset dns host ipv6	Available in user view

 

NOTE: 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

 

 

NOTE: By default, the Ethernet interface, VLAN interfaces, and aggregate interfaces are down. Before configuring them, bring them up with 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 packet forwarding.

[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

 

NOTE: ·       Before performing the following configuration, make sure that the device and the host are accessible to each another via available routes, and the IPv6 addresses of the interfaces are configured as shown Figure 2. ·       This configuration may vary with different DNS servers. The following configuration is performed on a PC running Windows server 2003. Make sure that 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:

# Enter the DNS server configuration page.

Select Start > Programs > Administrative Tools > DNS.

# Create zone com.

As shown in Figure 3, 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

 

# Create a mapping between the host name and the IPv6 address.

As shown in Figure 4, right click zone com.

Figure 4 Creating a record

 

In Figure 4, select Other New Records to bring up a dialog box as shown in Figure 5. Select IPv6 Host (AAA) as the resource record type.

Figure 5 Selecting the resource record type

 

As shown in Figure 6, type host name host and IPv6 address 1::1, and then click OK.

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

3.      Configuration verification:

# 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