conntrackd and init systems --------------------------- The conntrackd package comes preconfigured to use systemd [0]. You should use it. The sysvinit support was eventually dropped in version 1:1.4.4-1, but it was re-added due to popular request. To use sysvinit: * /etc/init.d/conntrackd * /etc/default/conntrackd To use systemd: You should use the systemd service file located in /lib/systemd/systemd/conntrackd.service. To customize it, copy that file to /etc/systemd/system/conntrackd.service so updates to the package don't destroy your changes or use the native systemctl edit mechanism [1]. [0] http://ral-arturo.blogspot.com.es/2016/08/why-conntrackd-in-debian-is-better-with.html [1] https://www.freedesktop.org/software/systemd/man/systemctl.html#edit%20NAME...