> updates can be made on any DNS server (e.g., "multi-master") This cannot be overstated. I'm currently in the process of trying to rehabilitate an existing D

> updates can be made on any DNS server (e.g., "multi-master") This cannot be overstated. I'm currently in the process of trying to rehabilitate an existing DNS infrastructure based on BIND, and it is a complete disaster. All the "high availability" stuff is focused around replicating zone databases from a single master to many slaves, which will indeed continue answering queries even if the master is down. It appears there is basically zero concern for ensuring that updates will continue to be accepted and distributed to slaves if the master fails. The documentation doesn't address it, and none of the many conversations I found through Google had good answers. I have no idea how large DNS installations are built on this software.