On Fri, Oct 23, 2009 at 12:22:52AM +1300, Perry Lorier wrote:
You could imagine extending this to other services such as NTP, but I'm not sure that you really would want to go that far, perhaps using DNS to lookup "_ntp._udp.local IN SRV" or similar to find your local NTP servers.
Another obvious approach might be to have a service discovery protocol where you send to a "service discovery" multicast group a message asking "wheres the nearest nameserver(s)?" then nameserver implementations could listen on this multicast group and reply. Again shared fate. This does have the downside of people running rogue nameservers and needing a "ServiceDiscovery-Guard" feature for switches....
ah... well - if your a router centric person, then you want to put everything into the tools you know and love. if your a dns centric person, then you put everything in the DNS. I point you to the "DISCOVER' opcode (experimental) in the DNS and the use of DNS over multicast for doing service discovery (e.g. Apples Bonjour)... Most of that is already designed/deployed and in pretty widespread use... over IPv4 or IPv6. And yes, its not RA/ND, or DHCP... its another configuration protocol and its not quite vendor specific. The best thing is, it pushes the smarts closer to the edge (the end device) and this makes me happy.
Personally I like the first option (anycast addresses) better, you can control who has access to your IGP and if your IGP is down, then for all intents and purposes your recursive nameservers are offline too :)
everyone to their own taste. --bill