Table of Contents

Firewall - iptables - Configure iptables for openvpn

Allow tcp connections on the openvpn port

iptables -A INPUT -i eth0 -m conntrack --ctstate NEW -p tcp --dport 1194 -j ACCEPT

NOTE: If udp is needed, then change the above accordingly.

  • The same applies if another port number is needed.

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 eth0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i eth0 -o tun+ -m -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

NAT the VPN client traffic to the Internet

iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE

NOTE: Change the IP address mask according to the info of the tun0 result while running “ip a” or “ifconfig” commands.

Allow outbound traffic through the vpn tunnel

iptables -A OUTPUT -o tun+ -j ACCEPT

Restart iptables

service iptables start