I want to set up ns1.DOMAIN.co.nz as the name serverOK, it doesn't sound like you can. I'll tell you our setup is that helps. We have clearfield.co.nz setup with NS's of ns1.clearfield.co.nz and ns2.clearfield.co.nz We also have clearfield.com setup with NS's of ns1.clearfield.com and ns2.clearfield.com. For .nz domains we tell our clients to use the ns?.clearfield.co.nz NS's and for .com domains tell them to use n?.clearfield.com. When we have to renumber we only update the registration details for 2 domains: clearfield.co.nz and clearfield.com (as they use ip addresses), none of our clients have to change their domain registration details (as they use names)