chicken egg problem

richard lucassen mailinglists at
Thu Jun 2 12:22:41 UTC 2016

On Thu, 2 Jun 2016 12:04:42 +0100
Simon Hobson <dhcp1 at> wrote:

[random assignment of DNS servers]

> You'll find it's more subtle than that !
> Assuming a preponderance of Windows clients, try assigning ",
>" and then take offline for a while. When you turn
> it back on, you'll probably find that few clients will use it again -
> until goes offline.
> I know of people who've empirically found that if they specify a
> local server before external resolvers, they can get a form of split
> DNS - where the Windows clients check with the local server first and
> then go to an external resolver if the first one doesn't have the
> answer. They then found that this breaks if the internal server ever
> goes offline - because then the clients put it to the end of the list
> "permanently" and it only gets promoted if others above it fail.

Sounds like a particular interpretation of an RFC. I've seen that
before :)

> IIRC there's also reports of Windows machines not changing settings
> (I suspect DNS servers was included) when the values change in the
> offers. Only if they lose their connection (lease expired, moved
> network, old lease no longer valid and NACKed) will they get a new
> lease and the new settings.

I think I'll stick to the simple idea to inverse DNS settings to some
ranges. Thnx for your time anyway!


richard lucassen

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