Install conntrack by entering the following commands in the terminal:
sudo apt update sudo apt install conntrack
Description:
Program to modify the conntrack tables
conntrack is a userspace command line program targeted at system administrators. It enables them to view and manage the in-kernel connection tracking state table.
Homepage: http://conntrack-tools.netfilter.org/
Version: 1:1.4.4+snapshot20161117-6ubuntu2
Section: net