iptables: what are counters? What is being counted and why?
In the iptables man page, I see many references to counters (e.g. see -Z option). What is being counted? What for? How is this useful?
I read many iptables tutorials, including the official documentation, but I never saw this properly explained.
The number of packets that match a given rule are counted. It provides an indication of how much traffic match each rule.
In the official documentation, there is something missing about iptables general concepts. Add this to it.