nftables

List all rules

$ sudo nft list ruleset

$ sudo nft add table inet [filter]

$ sudo nft add chain inet [filter] [input] '{ type filter hook input priority 0; }'

$ sudo nft add rule inet [filter] [input] tcp dport [22] accept

$ sudo nft delete rule inet [filter] [input] handle [5]

$ sudo nft -f [/etc/nftables.conf]

$ sudo nft flush ruleset

nft [options] [commands]

nftables is the modern Linux firewall framework replacing iptables. It provides a single unified interface for IPv4, IPv6, ARP, and bridge filtering.
nftables uses a new syntax and improves on iptables performance and functionality.

list

List objects.

Add object.

Delete object.

Flush objects.

Read commands from file.

Interactive mode.

Numeric output.

Different syntax from iptables. Replaces iptables, ip6tables, arptables, ebtables. Requires kernel support.

nftables was developed by the Netfilter project, authored primarily by Patrick McHardy and Pablo Neira Ayuso, released in Linux kernel 3.13 (2014).

iptables(8), firewalld(1), ufw(8), netfilter(7)