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Example: Configuring Recursive DNS Server Addresses for IPv6 Hosts

This example shows how to configure the recursive DNS server address of an IPv6 host. The recursive DNS server address is included in the router advertisement that is sent to the neighboring devices.


This example uses the following hardware and software components:

  • Two MX Series routers with IPv6 enabled on the connected interfaces.

  • Junos OS Release 14.1 or later running on all devices.


The example includes two routers that are directly connected. Configure IPv6 on the directly connected interfaces. Enable router advertisement on the interfaces and configure the recursive DNS server addresses and their lifetimes on the interfaces. This example verifies that the router advertisement sent to the neighboring device includes the configured recursive DNS server addresses.


Figure 1 shows the sample topology.

Figure 1: Configuring Recursive DNS Server Address for IPv6 HostsConfiguring Recursive DNS Server Address for IPv6 Hosts


CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Router R0

Router R1

Configuring the Recursive DNS Server Address

Step-by-Step Procedure

The following example requires that you navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.


Repeat this procedure for Router R1, modifying the appropriate interface names, addresses, and any other parameters for the router.

To configure the recursive DNS server address on Router R0:

  1. Enable IPv6 on the physical interface.

  2. Configure the loopback address.

  3. Specify the time interval between router advertisements on the interface.

    The router sends advertisements to neighbors after the specified time interval. In this example, Router R0 sends router advertisements to Router R1 after a minimum interval of 3 seconds and a maximum interval of 4 seconds.

  4. Configure the recursive DNS addresses and their lifetimes on the interface.


From configuration mode, confirm your configuration by entering the show interfaces and show protocols commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

If you are done configuring the device, commit the configuration.


Verifying That the Router Advertisement Includes the Recursive DNS Server Address


Verify that the router advertisement on Router R1 includes the recursive DNS server address configured on Router R0.


From operational mode on Router R1, enter the show ipv6 router-advertisement command.


The recursive DNS server address and the configured lifetime are included in the router advertisements on Router R1.