OpenSnitch is a GNU/Linux interactive application firewall inspired by Little Snitch. Opensnitch requires the opensnitchd rc script to execute upon startup. That is, add the following line to /etc/rc.local: [ -x /etc/rc.d/rc.opensnitchd ] && /etc/rc.d/rc.opensnitchd start To install the eBPF process monitor module (requires kernel-source), pass in eBPF=yes to the SlackBuild. The eBFP module additionally requires kernel support for KProbes (kernel probes) and syscalls tracing. README.SLACKWARE contains instructions for compiling a kernel with these features.