Netfilter/iptables/persistence

Ubuntu 18.04

apt install iptables-persistent netfilter-persistent

netfilter-persistent save
netfilter-persistent start

iptables-save  > /etc/iptables/rules.v4
ip6tables-save > /etc/iptables/rules.v6

systemctl status netfilter-persistent
systemctl stop    netfilter-persistent
systemctl start   netfilter-persistent
systemctl restart netfilter-persistent