DNS uses round robin...over time some requesting DNS servers will develop a
matrix that weights response times and will query based on which server has
the lowest weight (best response time). Not all DNS software does that
though.
If you REALLY need to send your users to the closest geographical server,
your best option is to do anycasting. It's a little difficult to set up and
definitely isn't for someone that doesn't understand how BGP works, but if
you can get it running, you are in like Flynn. Try googling F Root Anycast
and read up before you decide to go that route.
On Sat, Aug 16, 2008 at 10:04 PM, VK wrote:

> Hello,
> Please excuse my ignorance in this, but when I do a lookup, and the SOA has
> , say, 4 nameservers, which one would likely to repsond to me a
> geographically close NS? Or the primary first, or does it work on a "I
> don't
> care where you are" round robin principle?
>
> I am curious because I have 3 secondary servers about to be used, 2 in the
> U.S and 1 in the UK, along with the primary NS located here in my country,
> on a small (64k) ISDN line, which can be very congested at numerous times
> 24/7 due to the nature of the business. So, would it be more beneficial to
> have one of the international NS's act as primary? If it matters, there is
> about as much local as international traffic connections here, so choosing
> one ofver another for "best usage" would not really matter.
>
> TIA
>
>
>
>