What are the steps for a safe and reliable migration of a mail server from an old hardware to a new one, being changed OS, SW and so on?
Once the new machine is installed, the software is semi-configured what is the best way to replace the old server having the lowest down time ?
Any suggestion is very appreciated, especially keeping into account problems related to SSL certificates, IP address, DNS issues and so on. User account, aliases,and domains migration is not a real problem at the moment instead.