SMTP Interface for Connekt
This depends on systemd (>= 240-1~) so if you are on debian 9 you need to install it via backports.
apt install systemd -t stretch-backports
After that you can do a normal installation
# if installing directly via deb
apt install ./connekt-smtp.deb
# or via any repo
apt install connekt-smtp
You need to configure connekt endpoint and few other things
open /etc/default/csmtp in your favorite editor and make changes as per your need
API_ENDPOINT="http://127.0.0.1/v2/send/email/"
DEFAULT_APP="outbound"
ADDR="0.0.0.0:25"
service connekt-smtp (stop|start|status)