What is the story of DMZ in networks !

Imagine with me that you have a large palace, and this palace has a safe full of gold and jewels (representing the internal network of the company). The palace has a wall, and the wall has a guard (representing the firewall). But imagine that you have to allow some visitors to enter the palace in order to benefit from certain services, such as a public library or café (Internet servers). Here’s the problem: if every visitor enters the palace, what prevents him from delivering to the safe?

That’s why they invented something called DMZ or “demilitarized zone”. The idea is that it is a safe space between the palace and the outside world, where they put services that should be available to everyone, without jeopardizing the internal network.

What is DMZ?

A DMZ is a part of the network designed to serve as an additional line of defense. It is between the Internet (the outside world) and the company’s internal network. Goal? Protect sensitive information within the company, while at the same time providing services such as:

• Websites.
• Email servers.
• DNS and FTP servers.
• Proxy surfers.

How does DMZ work?

The idea is simple: if a connection comes from the Internet on a specific server within the DMZ, you have a firewall that monitors and determines if this connection is allowed to enter or not. If the hacker tries to bypass this wall, there is a second wall that prevents him from accessing the internal network.

Imagine it like this:

• The first wall to protect the DMZ.

• Servers in DMZ are “limited validity”, meaning that you can access the internal network.

• The second wall protects the internal network.

Even if a disaster happens and one of the DMZ servers is hacked, the rest of the network remains secure.

Why is DMZ important?

1. Reduces risk:

Instead of all network resources vulnerable to attacks, DMZ limits these threats. Services that need to be open to the world, such as websites and mail, are isolated.

2. Better access control:

You can determine who enters the Wash, and how it enters. I mean, even if there is a legitimate connection, you can monitor and filter it.

3. Protection from IP Spoofing attacks:

It has attacks in which the hacker tries to disguise himself as a reliable device. But DMZ easily detects and prevents these movements.

4. Prevents espionage:

Even if the hacker tries to explore the network and search for targets, they hit the firewall. The servers in the DMZ do not give it any information about the internal network.

Types of DMZ Design

* Single firewall:

• It has 3 interfaces:

1. Internet interface.
2. Interface for DMZ.
3. Interface for internal network.
• Its advantage is that it is economical and easy, but its security is less.

* Two firewalls:

• The first firewall protects the DMZ, and the second firewall protects the internal network.
• This method is more secure because it makes sensitive data harder to access.

Uses of DMZ

1. Companies and institutions:

For example, if they have websites or mail servers, they put them in the DMZ so that the internal network remains isolated.

2. With cloud systems:

Companies using services like Microsoft Azure can leverage DMZ to protect systems between cloud and on-premises infrastructure.

3. Protection of IoT and OT devices:

Equipment related to factories and production (Operational Technology) is often vulnerable to attacks, as the DMZ protects them by splitting the network and regulating traffic.