# /etc/systemd/system/iptables-restore.service
[Unit]
Description=Restore IPv4 and IPv6 firewall rules
DefaultDependencies=no
Before=network-pre.target
Wants=network-pre.target
After=local-fs.target

[Service]
Type=oneshot
ExecStart=/usr/sbin/iptables-restore /etc/iptables/ip4tables.rules
ExecStart=/usr/sbin/ip6tables-restore /etc/iptables/ip6tables.rules
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target