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.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

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.

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 ActionPurpose
    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 5end


    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

    Cisco IOS XE Release 3.8S

    Cisco IOS XE Release 3SE

    Cisco IOS XE Release 3.9S

    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.

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