An Anonymous Coward writes:
APNIC reminds us that "there are now a large number of ISPs, data centres, cloud services, and software that now support IPv6" and "enabling IPv6 can be as simple as clicking a button on your WiFi router."
I turned it on, with Comcast I received an IPv6 route but no DNS server. Fortunately, Google Public DNS has unmemorable addresses, which I was able to configure manually.
It works. "There's only one thing left for you to do: Turn it on!"
[ ed: What are the alternatives to Google's Public DNS? ]
You should get DNS servers from Comcast IPv6. It's a DHCPv6 exchange, and as long as your client accepts it you should have gotten 2001:558:feed::1 and ::2. For that matter, if your client supports it, you should be able to hint for a shorter prefix and get enough addresses for muliptle /64s. I can't remember if it's a /62 or a /60 for the shortest prefix it'll give out, as it's been a while since I tried. You can also manually get the DNS info from dns.comcast.net (redirects to dns.xfinity.com).
Why use DHCPv6 when SLAAC is perfectly capable of offering a DNS configuration?
Because SLAAC would only get you an address on your router, and the idea is to avoid NAT. DHCPv6 has the concept of Prefix Delegation. When you send a DHCPv6 Solicit message from a typical home gateway, you're requesting an IA_NA (Non-temporary address, which goes on the WAN port) and an IA_PD (Prefix Delegation: this goes on your whole LAN as typically a /64) so each of your connected devices has a routable address.
My Verizon router uses ICMPv6 to advertise a /64 prefix and a DNS server. Devices on my LAN take the prefix, pick addresses for themselves, and use the DNS server. There is no NAT.
I believe the parent meant that you're router could use DHCPv6 to get your LAN prefix from your ISP. Your local machines would use SLAAC to get their info from the router. That is, if the router uses SLAAC, it just gets an IP address and not the prefix it needs to broadcast to the LAN. It could then NAT the LAN through its IP, but the local LAN wouldn't have public addresses.