DHCPv6 Server Stateless Autoconfiguration

Hierarchical Dynamic Host Configuration Protocol for IPv6 (DHCPv6) for stateless configuration parameters allows a stateless or stateful DHCPv6 client to export configuration parameters (DHCPv6 options) to a local DHCPv6 server pool. The local DHCPv6 server can then provide the imported configuration parameters to other DHCPv6 clients.

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Information About DHCPv6 Server Stateless Autoconfiguration

DHCPv6 Server Stateless Autoconfiguration

Hierarchical Dynamic Host Configuration Protocol for IPv6 (DHCPv6) for stateless configuration parameters allows a stateless or stateful DHCPv6 client to export configuration parameters (DHCPv6 options) to a local DHCPv6 server pool. The local DHCPv6 server can then provide the imported configuration parameters to other DHCPv6 clients.

The figure below shows a typical broadband deployment.

Figure 1. Broadband Topology

The customer premises edge (CPE) interface toward the provider edge (PE) can be a stateless or stateful DHCPv6 client. In either case, the ISP-side DHCPv6 server might provide configuration parameters such as Domain Name System (DNS) server addresses, domain names, and Simple Network Time Protocol (SNTP) servers to the DHCP client on the CPE. Such information can be specific to ISPs.

In addition to being a DHCPv6 client (for example, toward the ISP), the CPE can act as a DHCPv6 server to the home network. For example, neighbor discovery followed by a stateless or stateful DHCPv6 client can occur on the link between the CPE and the home devices. In some cases, the information to be provided to the home network is the same as that obtained from the ISP-side DHCPv6 server. Because this information can be dynamically changed, it cannot be hard-configured in the CPE’s configuration. Therefore, the DHCPv6 component on the CPE allows automatic importing of configuration parameters from the DHCPv6 client to the DHCPv6 server pool.

DHCPv6 supports the options for IPv6 on the server described in the following sections.

Information Refresh Server Option

The DHCPv6 information refresh server option can specify a maximum limit for the length of time a client should wait before refreshing the information retrieved from DHCPv6. This option is used with stateless DHCPv6 because there are no addresses or other entities with lifetimes that can tell the client when to contact the DHCPv6 server to refresh its configuration.

NIS- and NIS+-Related Server Options

Users can configure the network information service (NIS) or NIS plus (NIS+) address or domain name of a DHCPv6 server using NIS- and NIS+-related options, and then import that information to the DHCPv6 client.

SIP Server Options

Session Initiation Protocol (SIP) server options contain either a list of domain names or a list of IPv6 addresses that can be mapped to one or more SIP outbound proxy servers. One option carries a list of domain names, and the other option carries a list of 128-bit IPv6 addresses.

SIP is an application-layer control protocol that can establish, modify, and terminate multimedia sessions or calls. A SIP system has several logical components: user agents, proxy servers, redirect servers, and registrars. User agents can contain SIP clients; proxy servers always contain SIP clients.

SNTP Server Option

The Simple Network Time Protocol (SNTP) server option provides a list of one or more IPv6 addresses of SNTP servers available to the client for synchronization. Clients use these SNTP servers to synchronize their system time to that of the standard time servers. The DHCPv6 server can list the SNTP servers in decreasing order of preference, but clients treat the list of SNTP servers as an ordered list.

How to Configure DHCPv6 Server Stateless Autoconfiguration

Configuring the Stateless DHCPv6 Server

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ipv6 dhcp pool poolname

    4.    dns-server ipv6-address

    5.    domain-name domain

    6.    exit

    7.    interface type number

    8.    ipv6 dhcp server poolname [rapid-commit] [preference value] [allow-hint]

    9.    ipv6 nd other-config flag

    10.    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 ipv6 dhcp pool poolname


    Example:
    Device(config)# ipv6 dhcp pool dhcp-pool
     

    Configures a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) configuration information pool and enters DHCPv6 pool configuration mode.

     
    Step 4 dns-server ipv6-address


    Example:
    Device(config-dhcp)# dns-server 2001:DB8:3000:3000::42
     

    Specifies the Domain Name System (DNS) IPv6 servers available to a DHCPv6 client.

     
    Step 5 domain-name domain


    Example:
    Device(config-dhcp)# domain-name example.com
     

    Configures a domain name for a DHCPv6 client.

     
    Step 6 exit


    Example:
    Device(config-dhcp)# exit
     

    Exits DHCPv6 pool configuration mode, and returns the device to global configuration mode.

     
    Step 7 interface type number


    Example:
    Device(config)# interface serial 3
     

    Specifies an interface type and number, and places the device in interface configuration mode.

     
    Step 8 ipv6 dhcp server poolname [rapid-commit] [preference value] [allow-hint]


    Example:
    Device(config-if)# ipv6 dhcp server dhcp-pool
     

    Enables DHCPv6 on an interface.

     
    Step 9 ipv6 nd other-config flag


    Example:
    Device(config-if)# ipv6 nd other-config flag
     

    Sets the “other stateful configuration” flag in IPv6 router advertisements (RAs).

     
    Step 10 end


    Example:
    Device(config-if)# end
     

    Returns to privileged EXEC mode.

     

    Configuring the Stateless DHCPv6 Client

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type number

      4.    ipv6 address autoconfig [default]

      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 serial 3
       

      Specifies an interface type and number, and places the device in interface configuration mode.

       
      Step 4 ipv6 address autoconfig [default]


      Example:
      Device(config-if)# ipv6 address autoconfig
       

      Enables automatic configuration of IPv6 addresses using stateless autoconfiguration on an interface and enables IPv6 processing on the interface.

       
      Step 5 end


      Example:
      Device(config-if)# end
       

      Returns to privileged EXEC mode.

       

      Enabling Processing of Packets with Source Routing Header Options

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    ipv6 source-route

        4.    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 ipv6 source-route


        Example:
        Device(config)# ipv6 source-route
         

        Enables processing of the IPv6 type 0 routing header.

         
        Step 4 end


        Example:
        Device(config-if)# end
         

        Returns to privileged EXEC mode.

         

        Configuration Examples for DHCPv6 Server Stateless Autoconfiguration

        Example: Configuring the Stateless DHCPv6 Function

        The following example shows how to use the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) function to configure clients with information about the name lookup system. The server is configured with a DHCP pool, which contains the name lookup information that is to be passed to clients. It does not need to contain a prefix pool. This DHCP pool is attached to the access link to customers (Ethernet 0/0) when you enter the ipv6 dhcp server command. The access link also has the ipv6 nd other-config-flag command enabled. Router advertisement (RA) messages sent from this interface inform clients that they should use DHCPv6 for “other” (for example, nonaddress) configuration information. 

        ipv6 dhcp pool dhcp-pool
 dns-server 2001:DB8:A:B::1
 dns-server 2001:DB8:3000:3000::42
 domain-name example.com
!
interface Ethernet 0/0
 description Access link down to customers
 ipv6 address 2001:DB8:1234:42::1/64
 ipv6 nd other-config-flag
 ipv6 dhcp server dhcp-pool

        The client has no obvious DHCPv6 configuration. However, the ipv6 address autoconfig command on the uplink to the service provider (Ethernet 0/0) causes the following two events:

        • Addresses are autoconfigured on the interface, based on prefixes in RA messages received from the server.

        • If received RA messages have the “other configuration” flag set, the interface attempts to acquire the other (for example, nonaddress) configuration from any DHCPv6 servers.

        Additional References for DHCP Overview

        Related Documents

        Related Topic

        Document Title

        Cisco IOS commands

        Cisco IOS Master Command List, All Releases

        DHCP commands

        Cisco IOS IP Addressing Services Command Reference

        IPv6 commands

        Cisco IOS IPv6 Command Reference

        IPv6 addressing and connectivity

        IPv6 Configuration Guide

        Cisco IOS IPv6 features

        Cisco IOS IPv6 Feature Mapping

        Standards and RFCs

        Standard/RFC

        Title

        RFC 951

        Bootstrap Protocol (BOOTP)

        RFC 1542

        Clarifications and Extensions for the Bootstrap Protocol

        RFCs for IPv6

        IPv6 RFCs

        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 DHCPv6 Server Stateless Autoconfiguration

        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 DHCPv6 Server Stateless Autoconfiguration

        Feature Name

        Releases

        Feature Information

        DHCPv6 Server Stateless Autoconfiguration

        Hierarchical DHCPv6 for stateless configuration parameters allows a stateless or stateful DHCPv6 client to export configuration parameters (DHCPv6 options) to a local DHCPv6 server pool.

        The following commands were introduced or modified: dns-server, domain-name, ipv6 address autoconfig, ipv6 dhcp pool, ipv6 dhcp server, ipv6 nd other-config-flag, ipv6 source-route.