The purpose of the NS record for the domain.

[Michael Voight]

Steven Sakata wrote:
> 
> I'm in the process of testing out Resonate's Global Dispatch software.  It's
> basically a smart DNS server (i.e., it will resolve DNS queries based on
> server availability, network latency between client and server, and load
> of server).  However, it only handles "A" records. 

Sounds like Cisco's DistributedDirector which I support. :)

If it is going to be the authoritative server for companyname.com, then
ALL companyname.com records must reside there unless you delegate them.

So, you would not be able to configure an mx record for companyname.com
on another server if you want all records to be reachable from the same
client. (as opposed to one server for internal people, one for external)

A client is only going to query one server (at a time) for
companyname.com. All the records the client needs should be on this one
server.
If you want to find an A record for host.companyname.com and it is not
on your dispatch server, then you would have to delegate the
host.companyname.com server to another machine. However, if your
Dispatch server doesn't allow this delgation, then this would be a
problem.

I don't see a way around it. For HTTP only, DistributedDirector does has
a http redirect mode to accomplish the issue of having a website for
companyname.com. Maybe the other product has this kind of feature.
The regular DNS server resolves the name, and DD accepts the connection
via a virtual address. It then redirects it to which ever server is most
available based on the metrics configured. 

Michael Voight
CSE, Cisco TAC