iptables - OpenVPN

#Incoming connections

iptables -A INPUT -i enp3s8 -m state --state NEW -p udp --dport 1194 -j ACCEPT

#Allow TUN interface connections to OpenVPN server

iptables -A INPUT -i tun+ -j ACCEPT

#Allow TUN interface connections to be forwarded through other interfaces

iptables -A FORWARD -i tun+ -j ACCEPT
iptables -A FORWARD -i tun+ -o enp3s8 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i enp3s8 -o tun+ -m state --state RELATED,ESTABLISHED -j ACCEPT

#NAT the VPN client traffic to the Internet. change the ip address mask according to your info of tun0 result while running "ifconfig" #command.

iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o enp3s8 -j MASQUERADE

#If your default iptables OUTPUT value is not ACCEPT, you will also need a line like:

iptables -A OUTPUT -o tun+ -j ACCEPT