For my own domains, I use rbldnsd on a couple of VM's in two datacenters with really high TTL's. No maintenance aside from the trivial yum update. At my workp

For my own domains, I use rbldnsd on a couple of VM's in two datacenters with really high TTL's. No maintenance aside from the trivial yum update. At my workplace we use Dyn and Verisign. I wanted to also have our own name servers, but folks didn't want to manage them.