[Unit]
Description=Sendmail Mail Transport Agent
After=network.target
Conflicts=postfix.service exim.service
Wants=sm-client.service

[Service]
Type=forking
PIDFile=/run/sendmail.pid
EnvironmentFile=/etc/default/sendmail
ExecStartPre=-/usr/bin/newaliases
ExecStart=/usr/sbin/sendmail -bd $SENDMAIL_OPTS $SENDMAIL_OPTARG

[Install]
WantedBy=multi-user.target
Also=sm-client.service