IPv6 SLAAC vs DHCPv6

Introduction to IPv6 Addressing

In IPv6, devices have multiple ways to acquire an IP address dynamically. The two primary methods are Stateless Address Autoconfiguration (SLAAC) and Dynamic Host Configuration Protocol version 6 (DHCPv6).

SLAAC (Stateless Address Autoconfiguration)

SLAAC allows a device to configure its own IPv6 address without the need for a central server.

How SLAAC Works

1. Router Solicitation (RS): The host sends a multicast message asking routers to identify themselves.
2. Router Advertisement (RA): Routers respond with an RA message containing the network prefix.
3. Address Generation: The host combines the network prefix from the RA with its own interface identifier (often derived from its MAC address using EUI-64 or randomly generated for privacy) to create a full IPv6 address.

DHCPv6 (Dynamic Host Configuration Protocol for IPv6)

DHCPv6 is similar to DHCP for IPv4. It uses a central server to assign IPv6 addresses and other network parameters to hosts.

Types of DHCPv6

• Stateful DHCPv6: The DHCP server provides the IPv6 address and keeps track of which host has which address (maintains state).
• Stateless DHCPv6: Used in conjunction with SLAAC. SLAAC provides the IPv6 address, and the stateless DHCPv6 server provides other information like DNS server addresses.