{"id":4553,"date":"2012-07-02T10:34:27","date_gmt":"2012-07-02T17:34:27","guid":{"rendered":"https:\/\/blogs.infoblox.com\/?p=4553"},"modified":"2022-10-19T15:58:18","modified_gmt":"2022-10-19T22:58:18","slug":"choosing-static-slaac-or-dhcpv6-part-3","status":"publish","type":"post","link":"https:\/\/www.infoblox.com\/blog\/ipv6-coe\/choosing-static-slaac-or-dhcpv6-part-3\/","title":{"rendered":"Choosing Static, SLAAC or DHCPv6? (part 3)"},"content":{"rendered":"

Here\u2019s the third entry of Cisco Press author and chair of the Rocky Mountain IPv6 Task Force\u00a0Scott Hogg<\/a>\u2019s multi-part blog on IPv6 addressing. This week: stateless and stateful DHCPv6. Thanks Scott! -Tom<\/p>\n

STATELESS DHCPV6<\/h4>\n

Another option is to have the client computers perform SLAAC but then use Stateless DHCPv6 to provide other information, such as DNS server, domain name, SIP server, to the clients.\u00a0 Stateless DHCPv6 Service for IPv6 is sometimes called DHCPv6 Lite.\u00a0 This approach is defined in\u00a0RFC 3736, Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6<\/a>.<\/p>\n

With Stateless DHCPv6, the client node performs SLAAC for its IPv6 address assignment and then sends DHCP Information Request and then router responds with a Reply message with info.\u00a0 DHCPv6-Lite can be performed easily on the local router.\u00a0 Cisco routers can perform Stateless DHCPv6 on their LAN interfaces.<\/p>\n

STATEFUL DHCPV6<\/h4>\n

The technique that most organizations prefer in many cases is to use Dynamic Host Configuration Protocol version 6 (DHCPv6) similarly to the way that DHCP is used within their networks for IPv4 address assignment.\u00a0 This protocol is specified in\u00a0RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)<\/a>.<\/p>\n

DHCPv6 operation starts with the router sending an ICMPv6 Router Advertisement (RA) message that indicates to nodes on the network that they should use DHCPv6 as their method of dynamic address configuration.\u00a0 The RA messages contain several bits (A, M, O, L bits) that indicate to the node how it should obtain its IPv6 address.\u00a0 This document has already covered the Address Autoconfiguration bit.<\/p>\n

The Managed Address Configuration Flag (M-flag or M-bit) determines if the host should use DHCPv6.\u00a0 When set to 1 it tells hosts to get stateful address through DHCPv6.<\/p>\n

The Other Stateful Configuration Flag (O-flag or O-bit) determines if the node should use DHCPv6 for other configuration information.\u00a0 When set to 1 it tells host to use DHCPv6 to get other configuration data.\u00a0 The O-bit is set to 1 for Stateless-DHCPv6 (DHCPv6-Lite) as described above.<\/p>\n

Following is a list of the typical combinations of address configuration bits set within the RA message sent by the local router.<\/p>\n