Debian rbldnsd package notes ============================ Socket activation ~~~~~~~~~~~~~~~~~ Socket activation is disabled by default in the service unit file, but it can be enabled with a drop-in: mkdir /etc/systemd/system/rbldnsd.service.d/ cat < /etc/systemd/system/rbldnsd.service.d/socketactivation.conf [Unit] Requires=rbldnsd.socket END systemctl daemon-reload systemctl stop rbldnsd.service systemctl start rbldnsd.socket If socket activation is used then the -b command line parameter will be ignored. Multiple instances ~~~~~~~~~~~~~~~~~~ Multiple instances of rbldnsd can be configured as usual in /etc/default/rbldnsd, but then each parametrized unit must be enabled: systemctl enable rbldnsd@mydnsbl systemctl start rbldnsd@mydnsbl