Openvpn - enabled redirect gateway but can't access any websites
do few things
1 ensure you have pkt forwarding enabled on vpn server:
cat /proc/sys/net/ipv4/ip_forward
it should be 1, if it's not run:
echo 1 > /proc/sys/net/ipv4/ip_forward
2 for a good measure add [ not really needed since you allow traffic from/to tun0.. ]
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
3 and finally - nat the traffic coming from vpn - that is: replace the source ip address of your connection with address of the server
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
i think the last point is the missing one...