Iptables Concepts

Internal

• iptables

netfilter, iptables tool, iptables service and firewalld

netfilter

netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called for every packet that traverses the respective hook.

iptables

iptables is a Linux userspace command line tool that manipulates the IPv4 network packet filtering rules. Packet filtering is most commonly used to implement firewalling functionality. It is also used to implement Network Address Translation (NAT).

ip6tables

ip6tables is the equivalent command line tool that manipulates the IPv6 network packet filtering rules.