This is a great place to express a concept that I have been trying to think through ... A secondary DNS or Mail server, ns2 or mail2, will operate until ns1 or mail1 is back in service. These systems expect the primary system to come back. They expect that they will always be the backup, the #2 to the #1. But if these #2 systems are truly mirroring the #1 systems then they should be able to take over, such that the #2 becomes the #1 and a new '2' system can get built and sync'd. A shuffle of hostnames and IP addresses would be required in such a transition but that's not a big deal. I've wondered if we could do the same with ISPConfig, promoting a slave to master if required, and just changing the "X is a mirror of Y" to re-assign roles. Is it more appropriate to think of a secondary box as always being a secondary? Or is this concept of succession a common/expected goal?