At 11:52 +0200 6/22/10, <[email protected]> wrote:
I see this rather so that a network causing issues for the host ought
to provide assistance for hosts to overcome those issues.
When I hear this, I think of the following analogy:
Because of foot surgery, I have to wear special inserts to my shoes.
It would be good if all the shoes would have the insert so that I
wouldn't have to remove and insert them each time I change shoes.
But building in the support I need to the shoes means that others
then can't use my shoes.
Infrastructure shouldn't try to cover up for host or application
specific issues.
From 10000 feet view some DNS servers have information others do not. Isn't
that enough of high level definition of split-DNS?
I wouldn't buy that definition. In some cases, it's different
information - the address for some name may be in both splits but be
different.
The DNS server selection is a mandatory feature for every host that receives
more than 1 DNS server address from any sources. In simplest case it just
means overwriting /etc/resolv.conf with the latest info received from
anywhere..
That's news to me.
It is a mistake for any application to know that there are multiple
DNS servers available, leave it to the DNS protocol to handle that.
The reason for multiple servers is resilience, based on the reliance
on UDP, and not for "feature shopping."
Maybe there is an overly optimistic impression of what you can do
knowing you have multiple DNS servers.
There was a good email "two reasons to have split-DNS" by Mark Andrews
last Friday. Won't those reasons remain valid reasons even in the presence
of multihomed hosts, hence unlikely to disappear any time soon? Hence need
to find a patch to the problem the solution caused.
There are more reasons than just the two, independent of multi-homed
devices. My theme is that this is a multi-homed device problem, not
a DNS problem.
What other criteria of selecting a DNS server could be in addition to FQDN
and IP-addresses (ranges, subnets)?
Target server availability and load. Routing traffic to the data
center that is active. Routing traffic to where people are staffed.
General traffic engineering. Dynamically creating answers to
questions. And so on.
Note - not all agree with the motives. I'm just saying that they are in play.
--
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Edward Lewis
NeuStar You can leave a voice message at +1-571-434-5468
The World Cup would be more fun if they didn't interrupt it with soccer games.
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