I'm looking to have some kind of backup MX server if my server should be cut off for any reason. Considering I'm using DirectAdmin, all the DNS info (and services) would be on the server for my clients. As I understand it, I would have to have a separate DNS box somewhere so I could actually point to a backup MX server.
What kind of specs would these servers need for say 100-150 domains and maybe 4-5 emails a day/per domain?
Am I right in this aspect? Or is there another alternative that would be better (aside from using another CP)?
