What is Netfilter?
Netfilter is a classic Firewall hacking tool used by many within the cybersecurity industry. The tool (framework) essentially filters packets inside Linux 2.4.x and later kernels. Netfilter is a series of hooks inside the Linux kernel that allows kernel modules to perform callback functions within the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack. iptables is a generic table structure for the definition of rulesets. Each rule within an IP table consists of a number of classifiers (iptables matches) and one connected action (iptables target). netfilter, ip_tables, connection tracking (ip_conntrack, nf_conntrack) and the NAT subsystem together build the major parts of the framework.
Is Netfilter Free?
Does Netfilter Work on all Operating Systems?
Its only for Linux operating systems.
What are the Typical Uses for Netfilter?
Netfilter allows the user to filter packets, network addresses along with ports, translations (within the NA[P]T protocols) and other packet auditing.