IPv6 DAD Proxy

IPv6 Duplicate Address Detection (DAD) Proxy feature responds to the DAD queries on behalf of a node that owns the queried address. It is useful in environments where nodes cannot communicate directly on the link.

Restrictions for IPv6 DAD Proxy

  • The IPv6 Duplicate Address Detection (DAD) Proxy feature is not supported on Etherchannel ports.

Information About IPv6 DAD Proxy

Overview of IPv6 DAD Proxy

The IPv6 Duplicate Address Detection (DAD) feature ensures that all the IP addresses assigned on a particular segment are unique. The process operates when IPv6 hosts directly communicate with one another where hosts cannot communicate directly, and a proxy is required.

After a host verifies that its address is unique, it enables the DAD procedure. However, when two hosts cannot communicate with each other, this procedure cannot detect a duplicate address. If the DAD procedure cannot run, both the hosts assigns the same link-local address, which causes both hosts to fail when they try to reach the Dynamic Host Configuration Protocol version 6 (DHCPv6 )server. The IPv6 DAD Proxy feature responds on behalf of the address owner when an address is in use.

The following figure provides an overview of the IPv6 DAD Proxy feature:

Figure 1. IPv6 DAD Proxy

How to Configure IPv6 DAD Proxy

Configuring IPv6 DAD Proxy

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. interface type number
  4. [no] ipv6 nd dad-proxy
  5. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:


Device(config)# interface GigabitEthernet 0/0/1

Specifies an interface type and number, and enters interface configuration mode.

Step 4

[no] ipv6 nd dad-proxy

Example:

Device(config-if)# ipv6 nd dad-proxy

Specifies if the ND suppress must operate in DAD-proxy mode.

In this mode, the DAD messages are not forwarded. They respond to an existing entry or are added to the binding table.

Step 5

end

Example:

Device(config-if)# end

Exits router interface configuration mode and returns to privileged EXEC mode.

Configuration Examples for IPv6 DAD Proxy

Example: Configuring IPv6 DAD Proxy 

Device> enable
Device# configure terminal
Device(config)# interface Ethernet 0/0 
Device(config-if)# ipv6 nd dad-proxy
Device(config-if)# end

Additional References for IPv6 DAD Proxy

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for IPv6 DAD Proxy

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for IPv6 DAD Proxy

Feature Name

Releases

Feature Information

IPv6 DAD Proxy

The following commands were introduced or modified: ipv6 nd dad-proxy , mode dad-proxy , mode md-proxy .