#!/bin/sh get_handle(){ local my_handle=$( nft -a list table $1|awk 'BEGIN{c0} /related,established/{c++; if (c==1) print $NF}' ) echo $my_handle } nft insert rule filter FORWARD tcp dport 53 drop nft insert rule filter FORWARD udp dport 53 drop handle=$(get_handle filter) nft add rule filter INPUT position $handle iifname "vif*" tcp dport 53 accept nft add rule filter INPUT position $handle iifname "vif*" udp dport 53 accept