External security

This is your first line of defense to keep your systems safe. It commonly comprises layer 2 or 3 firewalls, DDoS protection, web application firewalls, and other software and hardware. Before an attacker can compromise your application, they must first pass through these layers of hardware and software, which is not part of your application code, but is a shared infrastructure layer that many components in the application may share. In this section, we will look at some of this external security as well as some attacks that could be used against you. Securing the perimeter of your services is often a task completed by operations; however, as developers, we need to understand the processes and risks because it greatly enhances our ability to harden our application code. In this section, we will look at the common methods of external security and also some of the ways hackers can exploit your system.

Layer 2 or 3 firewalls

Layer 2 is more commonly used for routing, as it deals...