Re: Nice to See an Article About This
@Nigel - for me the decision between local/cloud is not really security, but getting a balance of performance & availability. Mail local to my home has best performance and availability for when I am at home, but considerably less so for when I am mobile. If I have my IMAP on AWS or similar, I have better availability and performance when I am mobile (I hope) but worse than when at home. Ideally I'd want a solution with two way replication of IMAP content, but on the other hand I want a solution that is simple and reliable. I think those might be mutually exclusive :)
@Vic - I agree with youur point about backup MX. In my case, my backup server is also Exim with the same spam configuration, and I use rsync to push whitelists and virtual domain lists to it from my main server. It works fairly well, although sometimes I get issues where the backup server has accepted mail that my main server later rejects, but this is handled relatively gracefully by Exim. I go for the backup MX route because I may from time to time turn off my whole home server for an extended period and I want to continue to accept mail. I have on occasion read the raw emails sitting in the mailqueue on my backup box while travelling. It's far from perfect, but works, in a clunky way, within my slightly odd parameters.