Ubiquiti IPv6 Prefix Delegation with SLAAC

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Here at the home office in Virginia we have an ISP that recently began offering IPv6 service to residential customers. Since we're running recent versions of Windows that prefer IPv6 connections to IPv4 I figured it was time to get onboard. The ISP we're using relies on IPv6 Prefix Delegation (PD) to provision IPv6 WAN addresses and assign /64 address prefixes for customer networks.

Prefix delegation by an ISP works by assigning a /128 address to a customer device, then routing a larger /64 (or bigger) prefix to that address. Provisioning of the /128 and adding the /64 prefix to the routing table is automated, all the customer needs to do is request the prefix be assigned.

On Ubiquiti routers with eth0 facing the ISP and switch0 facing the LAN. Here is my tested configuration:

ubnt@ubnt# show interfaces ethernet eth0
 address dhcp
 description Internet
 dhcpv6-pd {
     pd 0 {
         interface switch0 {
             service slaac
         }
         prefix-length 64
     }
 }
 ipv6 {
     address {
         autoconf
     }
 }
[edit]
ubnt@ubnt# _

The eth0 IPv6 address is configured for automatic address configuration. The dhcpv6-pd option is currently configured to only request a single prefix (pd 0) since it's only for a home network. The prefix-length 64 option requests a /64 network be provisioned by the ISP, and /64 is the smallest recommended prefix. Despite being the smallest prefix recommended it still has 18,446,744,073,709,551,616 total addresses.

The service slaac option set for switch0 configures the router to hand out addresses in the /64 prefix to local hosts on the LAN. With the configuration in place be sure to run the commit and save commands. The show ipv6 route command shows local IPv6 addresses, the /128 host address on the WAN, and the first /64 prefix address on switch0.

Configuring IPv6 for automatic addressing on Windows and Mac hosts assigns addresses in the /64 prefix and now you're online with IPv6!