In this chapter, we will begin to configure services that require communication between hosts over a network. Most Linux distributions will default to running a host-based firewall, iptables or firewalld. If you want your hosts to communicate with each other, you have two options: turn off iptables or configure iptables to allow the communication.
I prefer to leave iptables turned on and configure access. Keeping iptables is just another layer in your defence across the network. Host-based firewalls aren't a magic solution that will make your system secure, but they will block access to services you didn't intend to expose to the network.
Configuring iptables properly is a complicated task, which requires a deep understanding of networking. The example presented here is a simplification. If you are unfamiliar with iptables, I suggest...
