Re: Using IPv6 and ULA for greater resilience
On Sat, May 13, 2017 at 09:34:28AM +0200, Daniel Pocock wrote:
>
> - the aim is that if either the router or server stop working,
> everything else (e.g. local DNS, communication between other local
> machines) keeps working using the ULA prefix. Example: if the router
> stops working, the local workstations need to be able to resolve the
> hostname of the server and contact it using the ULA addresses.
To a first approximation, it sounds like what you really want
is multicast DNS, aka ZeroConf.
Or, in another direction, perhaps you want a failover DHCP and
DNS setup.
(And you can do both if you feel like it.)
If you do mDNS, every host will need to support it in order to
be reachable. They each act as a tiny DNS server, listening to
the multicast address in order to supply their own records (A,
AAAA, CNAME, whatever) and querying the multicast address for
either service discovery of a DNS server or the answer for their
request.
Failover DHCP is relatively easy, although less resilient
because you only need to disable all the participants to stop
your address assignment. Redundant DNS servers are nearly
trivial.
At home, I run failover DHCP and redundant DNS with my router
and my main server as the participants, both being Debian boxes.
I'm looking into mDNS, but only half-heartedly.
-dsr-
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