Receiving email

DBMail receives emails from a Message Transfer Agent (MTA) such as Exim or Postfix and delivers it via either the command line utility dbmail-deliver or the service daemon dbmail-lmtp.

When an email is received by your SMTP server for one of your users, it gets forwarded to either the command line utility dbmail-deliver or the dbmail-lmtpd LMTP service. dbmail-deliver might be preferable for lower volume or the LMTP server dbmail-lmtpd for higher volume.

Exim

Exim is a modern and highly configurable SMTP server that works well with DBMail. XML Team sponsored DBMail and an Exim configuration file is available on GitHub, though any MTA can send emails to DBMail through dbmail-deliver or LMTP. Either of the following two options work well.

dbmail_delivery:
  driver = pipe
  command = /usr/local/sbin/dbmail-deliver -d "$local_part_data@$domain_data"
  #command = /usr/local/sbin/dbmail-deliver -d "$address_data"
  return_fail_output
  user = mail

dbmail_delivery:
  driver = smtp
  protocol = lmtp
  hosts_avoid_tls = example.com
  hosts = example.com
  port = 24
  allow_localhost = true

DBMail's LMTP daemon should be protected from the internet, it should only receive emails from the MTA.