Mark Andrews wrote:
Hello Ray ,
On Wed, 12 Dec 2007, Ray Pelletier wrote:
Will all be changed to the following:
NS4.AMSL.COM 64.170.98.30
NS5.AMSL.COM 64.170.98.31
NS6.AMSL.COM 2001:5c0:9758::1:1
Fmi , Are the preceding name servers physically diverse ?
Tia , Jiml
There has to be common failure points with NS4.AMSL.COM
and NS5.AMSL.COM. Think route announcements.
Well, yes, of course.
The question that is more critical is, are there any elements which
aren't common failure points?
For them to meet physical diversity requirement there would
been to be /32's in the IRP.
I suspect you will find that they are just two boxes on the
same switch.
If the two IPs are on one physical server, there's very little that
could fail without taking down both instances.
(E.g. single disk failure, memory failure, NIC, crash/reboot, etc.)
If the two IPs were on different subnets, there would be an expectation
of physical diversity.
However, the same subnet makes this less certain, thus the OP's question.
Brian
You need both physical (power, hardware, location) and
operational (different global prefixes, preferably different
AS's) diversity for reliable DNS.
It's clear from the infomation above that the later is not
being met.
Mark
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Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews(_at_)isc(_dot_)org
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