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Re: Alternative to BGP-4 for multihoming?

  • From: Marc Slemko
  • Date: Tue Mar 14 11:37:23 2000

On Tue, 14 Mar 2000, Randy Bush wrote:

> > Once the client's DNS request has worked its way over to the primary DNS
> > for the distributed web-servers, 3DNS has each of the other 3DNS boxes
> > (located adjacent to the other distributed servers) ping the *clients*
> > primary DNS. 3DNS then returns the URL for the web-server whose 3DNS
> > machine is 'closest' (fewest hops) to the clients DNS machine.
> you may want to seriously reread the previous sender's message.  the point
> is that in the modern post-2182 world, many of the client's nameservers are
> vastly net.distant from the client.
> nameserver = DNS.LIBRARY.UCLA.EDU
> nameserver = RAIN.PSG.COM
> nameserver = ARIZONA.EDU
> it is best common practice.

Erm... no, not the nameservers for the domain the client is in, but the
nameserver doing the DNS lookup.

This will normally be a caching nameserver that may or may not be the same
as the nameservers for the domain.  In theory, it should be "close" to the
client network wise for other reasons.  Is it always?  No.  But it is a
more reasonable metric.  Not for best source, but for a reasonable

Saying "the clients's primary DNS" is misleading.  There is no way to know
what the "primary" DNS server is for a zone, and there may not even be
what is typically known as a primary.