**DHCPv6 Prefix Delegation (PD)**

VyOS supports DHCPv6 Prefix Delegation (DHCPv6-PD) as described in :rfc:`3633`. 
DHCPv6-PD is supported by most ISPs that provide native IPv6 for consumers on 
fixed networks.


.. cfgcmd:: set interfaces {{ var0 }} <interface> {{ var2 }} {{ var3 }}
  {{ var5 }} {{ var6 }} dhcpv6-options pd <id> length <length>

  **Configure a specific prefix length for DHCPv6-PD requests on this 
  interface.** 

  Some ISPs provide only a /64 prefix by default. Use this command to 
  request a different prefix length for a specific DHCPv6-PD request, 
  ranging from /32 (if allowed by your ISP) down to /64. <id> is a 
  unique identifier for the DHCPv6-PD request.

  The default value is 64.

  To request a /56 prefix from your ISP, use:

  .. code-block:: none

    set interfaces {{ var0 }} {{ var1 }} {{ var2 }} {{ var4 }} {{ var5 }} {{ var7 }} dhcpv6-options pd 0 length 56

.. cfgcmd:: set interfaces {{ var0 }} <interface> {{ var2 }} {{ var3 }}
  {{ var5 }} {{ var6 }} dhcpv6-options pd <id> interface <delegatee>
  address <address>

  **Configure the IPv6 interface identifier (host portion) for the delegatee 
  interface.**

  The value must be a decimal integer. It is appended to the delegated prefix 
  and the configured :abbr:`SLA ID (Site-Level Aggregation ID)` to form the 
  final IPv6 address.

  By default, the host portion is generated based on the parent interface's 
  MAC address (EUI-64 format).

   .. stop_vyoslinter

  **Example:**

  If a /64 prefix is delegated to interface eth8 and you configure the host 
  portion as 65535, the resulting IPv6 address will end with ::ffff, as 
  65535 corresponds to ffff in hexadecimal notation.

  .. start_vyoslinter


  .. code-block:: none

    set interfaces {{ var0 }} {{ var1 }} {{ var2 }} {{ var4 }} {{ var5 }} {{ var7 }} dhcpv6-options pd 0 interface eth8 address 65534

.. cfgcmd:: set interfaces {{ var0 }} <interface> {{ var2 }} {{ var3 }}
  {{ var5 }} {{ var6 }} dhcpv6-options pd <id> interface <delegatee> sla-id <id>

  **Configure the** :abbr:`SLA ID (Site-Level Aggregation ID)` **for the 
  delegatee interface.**

  The value must be a decimal integer greater than 0 and fit in the length of 
  SLA IDs. It is converted to hexadecimal and appended to the delegated prefix 
  to form the specific subnet prefix for the delegatee interface.

  **Example:** 

  If SLA ID is 1 and the delegated prefix is ``2001:db8:ffff::/48``, the 
  resulting subnet prefix for the delegatee interface will be 
  ``2001:db8:ffff:1::/64``.

  .. code-block:: none

    set interfaces {{ var0 }} {{ var1 }} {{ var2 }} {{ var4 }} {{ var5 }} {{ var7 }} dhcpv6-options pd 0 interface eth8 sla-id 1