Hello people. I was struggling - wondering if something like that is doable. Let's say we got 2-3-4-x servers which hosts emails using exim and dovecot. From time to time we move servers because they get old to new ones (migration) or moving busy mail domain accounts from one to another. Every single time I do that all mail users of the specific domain have issues. They need to re-login and re-authenticate to the new mail server, or they just can't receive or send emails because they got the old hostname on their configuration (Outlook (...) or thunderbird same issue). Most people are irrelevant with IT, they can't do it. They just can't So I was thinking for a future-proof solution (like the subject): Is it doable to setup a mail proxy / mail gateway and have a central hostname like mail.mydomain.com for all users - no matter in which server they are ? the mail.mydomain.com should be able to connect to the right server (digging MX ? whoising domain or having a DB with servers/domains/users? I don't know) and deliver the mail. So all users should have one specific domain in their smtp and pop3/imap settings. Is something like that possible ?