[Unit]
Description=Sendmail Mail Transport Client
After=network.target sendmail.service
Conflicts=postfix.service exim.service
BindTo=sendmail.service

[Service]
Type=forking
PIDFile=/var/spool/clientmqueue/sm-client.pid
EnvironmentFile=/etc/default/sendmail
ExecStartPre=/usr/bin/rm -f /var/spool/mqueue/xf*
ExecStart=/usr/bin/sendmail -L sm-msp-queue -Ac $SENDMAIL_OPTS $SENDMAIL_OPTARG

[Install]
WantedBy=multi-user.target