Re: How common is lack of DNS server diversity?

[John Hawkinson <jhawk () bbnplanet com>]

> For example, if you look at the name severs for GENUITY.NET
>
>   Domain servers in listed order:
>
>    DNSAUTH1.SYS.GTEI.NET      4.2.49.2
>    DNSAUTH2.SYS.GTEI.NET      4.2.49.3
>    DNSAUTH3.SYS.GTEI.NET      4.2.49.4
>
> They appear to be closely related.  However, the addresses are
> in fact routed to very diverse locations on Genuity's network.

However the 4/8 route is what is advertised to the world, and there
are certainly ocassions where that route fails to be propagated.

It's more diverse than adjacent nodes on an ethernet,
but hardly as diverse as would be ideal.

Ideally, all DNS servers for a site shouldn't be in the same autonomous
system.

--jhawk
  (who recently made the observation that there are VBNS-connected root
   nameservers, but not VBNS-connected gtld servers, so a hypotehtical
   site with a VBNS connection and a commodity connection has great
   difficulty using their VBNS connection to resolve VBNS names when
   the commodity connection goes down)