Exim 4 specifically configured to act as an outgoing SMTP service. Based on Debian Jessie.
list of allowed senders, separated by semicolon. Used within an Exim hostlist,
may include networks (
192.168.23.0/24 ; my.friend.example).
primary_hostname setting; you should also be able to specify
a hostname for your Docker container instead.
docker run -d -p 4444:25 -e PRIMARY_HOST=example.org -e ALLOWED_HOSTS="*" rickw/debian-exim-send