> I'm afraid that it would be difficult to maintain configuration across multiple DNS providers<p>A secondary host should be able to pull zones from the primary using standard AXFR, optionally using TSIG authentication. The primary can also notify a secondary using DNS NOTIFY for near instantaneous synchronization.<p>For some of my domains I prefer hosting primary myself, along with e-mail, web, etc. I just find it easier managing NSD configs and zone files the old fashioned way (version controlled, of course), rather than mucking about with GUIs or proprietary APIs. But in those cases I'll often use EasyDNS for secondary or tertiary. Whenever I edit and reload a zone file for one of these domains, NSD automatically pings EasyDNS, which then AXFR's the new zone. Easy peasy, at least once you wrap your head around AXFR, TSIG, and NOTIFY.<p>Your domain registrar is the gatekeeper for glue NS records, so if your primary DNS host[1] ever had a sustained down period, it's still relatively simple and fast to update your nameservers as needed.<p>[1] Yourself or another service--hopefully <i>not</i> the same as your registrar as that would defeat the purpose.