In a recent post, I discussed setting up an OpenVPN server on a Raspberry Pi. I relied on a nice tutorial from readwrite that you can find here. However, I found a discrepancy with the guide pertaining to its discussion of firewalls. The tutorial states that Raspbian has a firewall enabled by default. While iptables is certainly present by default (it’s part of the kernel), and it is often the basis for a very powerful firewall, it is not configured to be a firewall by default. Read on to learn how to enable a firewall on your Internet-facing Pi (including OpenVPN servers)!