In Chapter 5, Advanced Linux Administration, systemd was covered as a system and service manager. In systemd, there are several options to add an extra layer of protection to your daemons and filesystem.

To be honest, in our opinion, it really makes sense to use Azure Firewall on top of Azure network security groups. It is easy to set up, provides central administration, and requires almost no maintenance. It provides security between VMs, virtual networks, and even different Azure subscriptions.

Note

There is an additional cost if you want to use this firewall. However, a Linux firewall doesn't incur any charges as it is a security measure installed on your machine.

The choice between Azure Firewall and a Linux firewall depends on many things:

• Cost
• Deployment and orchestration of your VMs and applications
• Different roles: is there one administrator for everything?

I hope that after covering one of the Linux firewall implementations...