IPv6 devices can assign IP addresses to themselves.

This is known as "Stateless Addressing"

• No dedicated DHCP server
• No keeping track of IP or MAC addresses
• No lease times

The protocol is SLAAC (Stateless Address Autoconfiguration)

• A device automatically configures an IP address for itself without a DHCP server

DAD (Duplicate Address Detection) ensures that duplicate IPs are not used

NDP (Neighbor Discovery Protocol) - Discover other devices on a network

• IPv4 uses ARP, which uses broadcast
• NDP uses multicast

NDP also allows us to discover routers:

• Router Solicitation (RS) - Multicast by a device to all IPv6 routers
• Router Advertisement (RA) - Sent to a device in response to a solicitation OR multicast unsolicited

How SLAAC Works

1. Device determines what subnet it is on using RS through NDP
2. Router responds with an RA, device now knows the 64-bit subnet prefix
   • Remember, IPv6 addresses are 128 bits
3. Last 64 bits are often made from the device's MAC addresses with "ff:fe" in the middle or randomized
4. Before using the IP, DAD is used to check the network if that IP is being used