After installing OpenVPN on a VPS running Linux (i.e. Ubuntu), my website that was hosted on that VPS running Apache webserver was no longer reachable. When I tried to connect to that website, the connection timed out.

Apparently, something was messing with the functionality of Apache, which no longer worked properly. Apache was running fine when I check the status of the service:

root@ubuntu:/# service apache2 status
 * apache2 is running

I had been working on the firewall when installing OpenVPN, as well as packet forwarding. Because this VPS is running within OpenVZ (a container-based virtualization for Linux), I had to make some changes.

1. Go to your OpenVZ configuration panel and enable TUN/TAP.
2. Reset the IPtables (see below), the -P paramter stands for ‘Policy’
3. Flush everything (see below), the -F paramter stands for ‘Flush’, and then try to reload the website that was previously down!

iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

iptables -F INPUT
iptables -F OUTPUT
iptables -F FORWARD