Exploring networks and data flows

Network architecture is about how the building blocks of the networks are connected; data flows are about the information that flows through the network.

Understanding the network architecture will assist us in understanding the weak points of the network. Data flows can be manipulated by attackers to steal information from the network. By diverting them in the attacker's direction, the attacker can watch information running through the network and steal valuable information.

To eliminate this from happening, you must understand the structure of your network and the data that flows through it. A typical data network is built out of three parts:

• The data center, which holds the organization's servers and applications.
• The core network, which is the part of the network that is used to connect all the parts of the network, including the user's network, the data centers, remote networks, and the internet.
• The user's network, which is the part of the network that is used for the user's connectivity. The user network is usually based on the distribution and access networks.

These parts are illustrated in the following diagram:

Figure 1.1 – Typical enterprise network

In the top-left corner, we can see the main data center, DC-1. The user's network is located in the data center site; that is, USERS-1. In the top-right corner, we can see a secondary data center, DC-2, with a user's network located on the secondary data center site. The two data centers are connected to the internet via two firewalls, which are located in the two data centers.

In the center of the diagram, we can see the Wide Area Network (WAN) connectivity, which includes the routers that connect to the Service Provider's (SP's) network and the SP network that establishes this connectivity.

In the lower part of the diagram, we can see the remote sites that connect to the center via the SP network.

Now, let's focus on the protocols and technologies that are implemented on each part of the network.