nftables Beginner Examples

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The first things you need to do and the commands that you need. Save and Translate your iptables rule into nftables rules when migrating from iptables to nftables are:

Save iptables rules to text file

iptables-save -c > iptables-saved-backup.txt

Translate iptables rules to nftables text file

iptables-restore-translate -f iptables-saved-backup.txt > ruleset.nft

Active nftables rules

nft -f ruleset.nft

NOTE

You should remove/purge iptables or (as in one case) the server can lock up. On another server I experienced no problem having both installed (but only using nftables). 

apt purge iptables

A simple example nftables input chain

chain input { 
type filter hook input priority 0;
ct state established,related counter accept;     
ct state invalid counter drop;     
tcp dport {22, 80, 443} ct state new counter accept;     
ip saddr @my_ipv4_addrs counter accept;     
ip6 saddr @my_ipv6_addrs counter accept; 
}

List nftables Rules

nft list table filter

Flush nftables rules

nft flush ruleset

Save backup of nftables rules to file

nft list ruleset > /etc/nftables.rules

Test your nftables firewall with the following command

sudo -- sh -c 'nft -f /etc/nftables.conf; sleep 30; nft flush ruleset'

This will activate the firewall and reset it after 30 seconds. This test prevents locking yourself out of your server.

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