The Dynamic Host Configuration Protocol version 6 is a network protocol for
configuring Internet Protocol version 6 hosts with IP addresses, IP prefixes and
other configuration data required to operate in an IPv6 network. It is the
IPv6 equivalent of the Dynamic Host Configuration Protocol for IPv4.
IPv6 hosts may automatically generate IP addresses internally using stateless
address autoconfiguration, or they may be assigned configuration data with
DHCPv6. IPv6 hosts that use stateless
autoconfiguration may require information other than an IP address or
route. DHCPv6 can be used to acquire this information, even though it is not
being used to configure IP addresses. DHCPv6 is not necessary for configuring
hosts with the addresses of Domain Name System servers, because they can be
configured using Neighbor Discovery Protocol, which is also the mechanism
for stateless autoconfiguration. Many IPv6 routers, such as routers for
residential networks, must be configured automatically with no operator
intervention. Such routers require not only an IPv6 address for use in
communicating with upstream routers, but also an IPv6 prefix for use in
configuring devices on the downstream side of the router. DHCPv6 prefix
delegation provides a mechanism for configuring such routers.
Operation = Port numbers =
DHCPv6 uses UDP port number 546 for clients and port number 547 for servers.
= DHCP Unique Identifier = The DHCP Unique Identifier is used by a
client to get an IP address from a DHCPv6 server. It has a minimum length
of 12 bytes and a maximum length of 20 bytes. Its actual length depends on its
type. The server compares the DUID with its database and delivers configuration
data to the client. The first 16 bits of a DUID contain the DUID type, of which
there are three types. The meaning of the remaining 96 bits depend on the DUID
type. = Example =
In this example, the server's link-local address is fe80::0011:22ff:fe33:5566 and
the client's link-local address is fe80::aabb:ccff:fedd:eeff.
DHCPv6 client sends a Solicit from [fe80::aabb:ccff:fedd:eeff]:546 for
[ff02::1:2]:547. DHCPv6 server replies with an Advertise
from [fe80::0011:22ff:fe33:5566]:547 for [fe80::aabb:ccff:fedd:eeff]:546.
DHCPv6 client replies with a Request from [fe80::aabb:ccff:fedd:eeff]:546 for
[ff02::1:2]:547. DHCPv6 server finishes with a Reply from
[fe80::0011:22ff:fe33:5566]:547 for [fe80::aabb:ccff:fedd:eeff]:546.
IETF standards RFC 3315, "Dynamic Host Configuration
Protocol for IPv6" - Updated by RFC 6221, RFC 4361
RFC 3319, "Dynamic Host Configuration Protocol Options for Session Initiation
Protocol Servers" RFC 3633, "IPv6 Prefix Options for
Dynamic Host Configuration Protocol version 6"
RFC 3646, "DNS Configuration options for Dynamic Host Configuration Protocol for
IPv6" RFC 3736, "Stateless Dynamic Host
Configuration Protocol Service for IPv6" RFC 5007, "DHCPv6 Leasequery"
RFC 6221, "Lightweight DHCPv6 Relay Agent" - Updates RFC 3315, Errata
See also Comparison of DHCP server software
Neighbor Discovery Protocol, which also supports DNS Configuration
References External links
IPv6 Intelligence: DHCPv6, comparison of DHCPv6 packages and implementations
IPv6 Ready: DHCPv6, list of IPv6 Phase II Certified DHCPv6 implementations