First of all, all credits go to @YukiteruAmano, because this post is based on the tutorial you posted on the forum. The difference is that I am going to focus on Arch, although it will probably work for other distros based on systemd.
What is Firehol?
Firehol, is a small application that helps us to manage the firewall integrated into the kernel and its tool iptables. Firehol, lacks a graphical interface, all configuration must be done through text files, but despite this, the configuration is still simple for novice users, or powerful for those looking for advanced options. All that Firehol does, is simplify the creation of iptables rules as much as possible and enable a good firewall for our system.
Installation and configuration
Firehol is not in the official Arch repositories, so we will refer to AUR.
yaourt -S firehol
Then we go to the configuration file.
sudo nano /etc/firehol/firehol.conf
And we add the rules there, you can use these.
Keep activating Firehol for each startup. Pretty simple with systemd.
sudo systemctl enable firehol
We started Firehol.
sudo systemctl start firehol
Finally we verify that the iptables rules have been created and loaded correctly.
sudo iptables -L
As firehol does not handle ip6tables and since most of our connections do not have support for IPv6, my recommendation is to disable it.
En Arch we add ipv6.disable = 1 to the kernel line in the / etc / default / grub file
Now we regenerate the grub.cfg:
sudo grub-mkconfig -o /boot/grub/grub.cfg
En Debian enough with:
sudo echo net.ipv6.conf.all.disable_ipv6=1 > /etc/sysctl.d/disableipv6.conf