I am migrating a mailserver running sendmail
8.14.3 to a postfix server. The
MDA on the new server is
Dovecot. In order to ensure a seamless transition, it would be best if incoming mails are delivered to both servers simultaneously.
I've heard about the
nullcient options in sendmail, but I'm not sure if this works in the way I need it to. What I need is all incoming mails also delivered to the new server, leaving the existing configuration untouched, as they should be delivered to the mailboxes on the old server as well.
Mails are sent to an address like
firstname.lastname@example.org and should be delivered to
mx1.mydomain.com (old) and
mx2.mydomain.com (new). So
mx1 should forward a copy to
Dual MX Records are not enough as the one server would only be contacted when the other one isn't reachable - while both should be receiving the mail.
Maybe another option would be to configure
sendmail to deliver directly to
Dovecot on the new server via
lmtp? Or maybe just
rsync the mailboxes on the two servers. But I'm not sure if that's compatible.
UPDATE: It's not the same format: on the old server, there are just plain old files for each mailbox, while
Dovecot creates a
tmp structure in each user's mail directory. However, in the end, files with a similar format reside in those directories. The speration string is different though. Maybe it's possible to translate the old format and copy it to the new server periodically? Would that somehow interfere with
Dovecot? And where could I place the copies on the new server so that
Dovecot won't be affected while still recognising them?
I hope there is some kind of workaround for that.
Number of mailboxes: ~100-200
OS: Debian GNU/Linux 6.0 sendmail 8.14.3 mails are delivered to "real"/"passwd" users Other Serives: apache2, mysql, other miscellaneous
OS: Debian GNU/Linux 9 postfix dovecot mails are delivered to virtual users/SQL Other services: apache2, mysql, other miscellaneous
Current MX entry for reference:
mydomain.com. IN MX 0 mx1.mydomain.com. mydomain.com. IN MX 1 mx2.mydomain.com.