opens iptables nat access for zerotier and eth

 #sudo sysctl -w net.ipv4.ip_forward=1

#PHY_IFACE=eth0; ZT_IFACE=ztmjfkb3mw

#sudo iptables -t nat -A POSTROUTING -o $PHY_IFACE -j MASQUERADE

#sudo iptables -A FORWARD -i $PHY_IFACE -o $ZT_IFACE -m state --state RELATED,ESTABLISHED -j ACCEPT

#sudo iptables -A FORWARD -i $ZT_IFACE -o $PHY_IFACE -j ACCEPT

#sudo apt install iptables-persistent

#sudo bash -c iptables-save > /etc/iptables/rules.v4