📄️ iptables
iptables is a user-space utility that allows a system administrator to configure the IP packet filter rules of the Linux kernel firewall, implemented as a set of Netfilter hooks. For many years, it has been the standard tool for firewalling on Linux.
📄️ Netfilter Framework
Netfilter is the underlying packet filtering framework within the Linux kernel. It is not a tool that users interact with directly, but rather a powerful infrastructure that provides a series of "hooks" into the kernel's network stack.