© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Advanced IPv6 Topics Understanding DHCPv6 Operations

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v DHCPv6 DHCPv6: an updated version of DHCP for IPv6 Supports new addressing Allows more control than stateless autoconfiguration Can be used for renumbering Can be used for automatic domain name registration of hosts using DDNS

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v DHCPv6 Operation Same as in IPv4, with these exceptions: Client first detects the presence of routers on the link. If found, then examines router advertisements to determine if DHCP can be used. If no router found or if DHCP can be used: –Sends DHCP solicit message to the all-DHCP-agents multicast address –Uses the link-local address as the source address

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v DHCPv6 Multicast Addresses Multicast addresses used: FF02::1:2 = all-DHCP agents (servers or relays), link-local scope FF05::1:3 = all-DHCP servers, site-local scope

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Basic DHCPv6 Configuration Relay Agent (config-if)# ipv6 dhcp relay destination ipv6-address DHCPv6 Server (config)# ipv6 dhcp pool poolname (config)# ipv6 dhcp server poolname

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary DHCP has been updated to support IPv6, including the ability to work with stateless autoconfiguration. IPv6 hosts use DHCPv6 when there is no router present on a link, or a router advertisement instructs them to do so. The DHCPv6 specification allows the use of multicast addresses to support forwarding of messages from DHCPv6 relays to DHCPv6 servers, although Cisco does not support that functionality.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.03-7