iptablesnftables

Iptablesnftables refers to the relationship and coexistence between the traditional iptables firewall interface and the newer nftables framework in the Linux Netfilter project. Iptables is the historic user-space toolset that interacts with the kernel’s legacy filtering hooks, while nftables provides a unified, modern rule language and a single tool (nft) capable of configuring IPv4, IPv6, and other protocols through a consolidated backend.

During the transition from iptables to nftables, many Linux distributions provide compatibility layers that let administrators continue using iptables commands while actually configuring the nftables backend. Packages such as iptables-nft implement the nftables backend behind iptables-compatible tools, whereas iptables-legacy exposes the older, legacy backend. The system’s alternatives mechanism is often used to switch between these backends without rewriting rules.

In practice, nftables introduces a different rule syntax based on tables, chains, and sets, which can seem unfamiliar to those used to iptables. To ease migration, tools like iptables-translate can convert iptables rules into nftables syntax, and the nft tool can be used directly to manage rulesets. The goal of the iptables/nftables ecosystem is to provide a gradual upgrade path: maintain compatibility for stability and familiarity, while encouraging migration to nftables for new deployments due to its streamlined design, extensibility with sets and maps, and unified handling of multiple address families.

Migration considerations include rule portability, feature parity, and performance. While iptables remains viable for existing setups, nftables is generally recommended for new configurations, with translation and compatibility options available to bridge the two approaches.