User Manual
UMN:CLI
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DHCPv6 Address Assignment Mechanism
DHCP for IPv6 can provide stateful address configuration or stateless configuration set-
tings to IPv6 hosts. IPv6 hosts use several methods to configure addresses:
-
Stateful Mechanism
It obtains interface address and configuration information from DHCP server. A site
requires tighter control over exact address assignment.
-
Stateless Mechanism
It allows a host to generate its own address using a combination information adver-
tisement by routers. A site is not concerned with the exact address hosts use.
DHCPv6 Message Types
There are 13 DHCP message types. The following table summarizes the DHCP message
types.
DHCPv6 Message
Value
Description
Solicit
1
Sent by clients to locate DHCPv6 servers.
Advertise
2
Sent by server as a response to Solicit message received from a client to
indicate that it is available for DHCP service.
Request
3
Sent by clients to request configuration parameters, including IP address
or delegated prefixes, from a specific server.
Confirm
4
Sent by clients to verify that their address and configuration parameters
are still valid.
Renew
5
Sent by clients to renew their configuration parameters with their original
DHCP server when their lease is about to expire.
Rebind
6
Sent by client to extend the lifetime of their address and renew their
configuration parameters with any DHCP server when their lease is
about to expire
Reply
7
Sent by DHCP servers responding to Request, Confirm, Renew, Rebind,
Release, and Decline messages.
Release
8
Sent by clients to release their IP address
Decline
9
Sent by clients to indicate that one or more addresses assigned to them
are already in use on the link.
Reconfigure
10
Sent by DHCP servers to inform clients that the server has new or up-
dated configuration information. The clients then must initiate a request
in order to obtain the updated information.
Information-request
11
Sent by clients to request configuration parameters without the assign-
ment of any IP addresses to the client.
Relay-forward
12
Sent by DHCP relays to forward client messages to servers. The relay
encapsulates the client message in an option in the relay-forward mes-
sage.
Relay-reply
13
Sent by DHCP servers to send messages to clients through a relay. The
client message is encapsulated as an option in the relay-reply message.
The relay decapsulates the message and forwards it to the client.
Tab. 9.4
DHCPv6 Message Types
