Understanding Security Zones Internal DMZ and Border

Security Zones

Security Zones are firewall configurations that allow you to control levels of security applied in different areas. Firewall security zones operate by blocking or allowing certain kinds of network traffic based on firewall rules created for each zone. The firewall “routes” the data to allow it through if needed, and blocks it if not.

A firewall can be set up with one, two or three zones. The three firewall security zones are Internal, Demilitarized Zone (DMZ) and External.


The most secure zone is the “internal” one since it has no connection to a public network or internet service provider. This prevents any attacks from outside sources that could potentially harm your business’s network.

Internal zone is where we keep all internal servers and workstations. Internal zone is where servers are located with the most sensitive information like databases and file shares. Internal firewall is used to protect this zone from unauthorized access.

Demilitarized Zone (DMZ)

A firewall with two zones, or a “DMZ firewall,” allows you to create an additional zone between the internal and external zones. This provides protection from both inside threats, as well as attacks from outside sources. 

A demilitarized zone (DMZ) firewall is a firewall that separates two or more networks, allowing them to communicate with each other securely. The firewall itself is often referred to as “the demilitarized zone” because it sits between these two networks and serves a similar role – keeping them separate while allowing communication. 

Severs that are behind DMZ firewall are excluded from firewall policies and can be accessed by the public . This firewall can be set up to protect public-facing servers, such as web or mail.

External (Border Firewall)

A firewall with three security zones is referred to as a “border firewall.” The border firewall’s third zone sits in front of your network, which protects it from outside attacks.

External firewall is a firewall that is normally placed between an internal network and the Internet. The firewall will block any incoming traffic (from outside) to your internal network which can be annoying if you want to access something like a web server, mail server or VPN services from the internet side of things.

You may then need to set up rules for these exceptions in the firewall. A border firewall is a firewall that sits between the public Internet and your internal network, and it controls external traffic to prevent potential threats from reaching your private environment. – If you’ve ever set up firewall rules on your home router or security product before, you can think of this as having an even more granular way to control what IP address you’re allowing into your private network.

Inside and Outside Network

The network behind the firewall is often referred to as “the inside” and typically contains sensitive data like financial records, customer information, etc.. This network should not be accessible directly from the Internet, as it would pose a security risk. The firewall is designed to prevent any unauthorized access from outside the firewall and even within some cases.

The network on the other side of the firewall (the “outside”) typically contains resources that are meant for public use such as websites or email services . This section can be accessed by anyone, but the firewall will prevent any host on the inside network from accessing anything here.

How does firewall security differ between firewall zones? 

Since all the rules are applied on one firewall, it is important to keep track of them and make sure they’re configured correctly – otherwise you may block traffic that needs to pass through or allow in attacks from outside your network. This is why having a firewall with different security zones can be helpful.

How do firewall security zones work with different protocols? 

Firewall rules are typically set up to allow or block certain kinds of data. For example, if your firewall is configured for a “DMZ firewall” you might create firewall rules that only allow web traffic through the firewall while blocking other types like email and FTP. The firewall would be configured to allow web traffic through (since it’s what the firewall was designed for) and block everything else.

The firewall might also be configured with “internal” security zone rules that only allow internal network hosts access to specific websites, but blocks all other types of outside traffic like email or Skype requests.

What firewall security zones should you use? 

The firewall configuration that best fits your needs will depend on what systems and data are included in each zone, as well as how they’re used by those inside the network. For example, if there is separate company for managing DNS servers then it might make sense to create two firewall zones – one for the firewall itself and another to separate DNS traffic from other kinds of network traffic.

How does a firewall with security zones compare to a firewall without? 

Firewall security zones allow you more control over how your firewall operates, which can be especially helpful if there are many different types of data or devices that must pass through it. If you’re not sure which firewall type to use, firewall security zones can be configured in many different ways depending on your needs.


Based on the article above, firewall security zones are a great way to configure your firewall rules. You can create firewall rules that allow specific traffic through, block certain kinds of data from entering, and separate different types of network devices or data.

A firewall will protect your network from outside attacks and give you more control over what can enter or exit the firewall. A DMZ firewall is one configuration of firewall security zones that allows for better organization within the firewall rules, but it’s also important to keep track of all these rules since they’re applied on a single device! 

Today’s Internet is much more complex than it was even ten years ago – with the rise in VPNs for remote access as well as more and more Internet of Things devices, firewall security zones can be the best way to configure your firewall.

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