I'm going eventually to replace my current mailserver solution (free version of mailcleaner; mailcleaner.org) with iRedAdmin-Pro for MySQL backend, but missing a few features:
per domain configurable smtp-callout to an another system (if the domain is forwarded to another host)
per user/domain/server configurable archiving method which sends the messages without any adresschanges to another host:port
just like it is possible with amavisd for the whole server:
$archive_quarantine_method = 'smtp:[212.79.184.19]:2500'; #
# $archive_quarantine_to = 'archive-quarantine'; # rewrite local part of recipient address
$archive_quarantine_to = '%a'; # keep recipient address
@archive_quarantine_to_maps = (\$archive_quarantine_to);
$mailfrom_to_quarantine = undef; # undef keeps original senderper user/domain/server configurable spam/quarantine reporting (with configurable mail teplates) and an user interface to release such messages
one button (and cmd) backup/restore for configuration and/or content to activate an already prepared standby system in a very short time
domain-aliases
customer has several domains which all have the same settings and are all forwarded to the same mailbox server (i.e. ms-exchange)