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Re: Transitioning IETF DNS services

2007-12-12 23:14:04

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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