#!/bin/sh

nft add table ip nat
nft -- add chain ip nat prerouting { type nat hook prerouting priority -100 \; }
nft add chain ip nat postrouting { type nat hook postrouting priority 100 \; }

for port in 20 21 53 80 443; do
    nft add rule ip nat prerouting tcp dport ${port} redirect to :22
done