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Firewall System Design Service


Firewalls are the primary line of defense that protects the internal network of an organization from cyber attackers and Internet threats and restricts unauthorized access. But simply installing a firewall won’t solve the problem. Even if the vendor’s offer seems promising, you have to understand how to efficiently integrate the firewall into your existing systems.

This infrastructure is mission-critical, which is why designing a firewall system implies making crucial decisions about an organization’s system security and the ways to enforce it. This includes:

  • determining the problems to solve
  • outlining the architecture
  • choosing firewall features
  • considering using dual firewalls
  • selecting a firewall vendor
  • establishing the system and security requirements
  • defining the rules and policies defending the private network


Having an effective, simple-to-manage, and scalable firewall system design is integral for businesses for several reasons:

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It determines the strength of the firewall’s security
It lays down how well the firewall will perform over time
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It outlines which policies can be enforced
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Bad architecture choice = costly post-deployment do-overs


A high-quality firewall system design answers many vital questions like:

  • Which risks do you want to avoid using the firewall?
  • What’s the firewall location within your systems, and which segments will it protect?
  • Which services are required?
  • What is the expected performance?
  • Who will manage the firewall system?
  • How are the system and network expected to grow?

It’s like a blueprint outlining all the network security essentials. So, if an organization has trouble making such tough decisions, turning to professionals for a consultation on firewall system design can save a lot of trouble down the line.


Although firewall system design can be taken care of at any point, ideally, this is a step that takes place before you even purchase a firewall (i.e., prior to or during firewall sizing). In fact, the requirements indicated in the design directly affect vendor selection and the functions the firewall must have.

A lot of things depend on the firewall’s location within the system and what it’s supposed to protect. For example, this regards how much network traffic it’ll process, its size, and the must-include firewall functions.

Such decisions are often impossible to make correctly without in-depth experience. Hence, turning to firewall professionals like OutsourceIT.PRO’s team that offers a firewall system design service can be a safety net.

Have questions about the design service of firewall systems?


How does the firewall system design process work? Here are the common steps that OutsourceIT.PRO follows when designing a firewall system. We fall back on the best practices recommended by CERT.

Step 1: Detailed analysis

Firewall system design starts with the analysis of the current environment. During this step, we review the needs and tasks the firewall should accomplish, noting the core security requirements. This will influence most consequent decisions like the appropriate firewall size you need, which vendor is optimal, how the firewall should protect the network, how to configure the firewall, and so on.

Step 2: Deciding on the basic architecture

We continue by choosing the basic components of firewall architecture. Usually, this starts with single-layer vs. multi-layer architecture, how many hosts there will be, how they’ll be connected, and the tasks they’ll perform.

With single-layer architecture, all the firewall functions are in a single network host. It’s a straightforward and cost-saving approach that’s applicable for a few interconnected networks. But it’s generally more prone to penetration in cases of misconfigurations or errors.

The firewall functions in multi-layer architecture are split between several network hosts that are commonly connected with demilitarized zone (DMZ) networks. This layered dual firewall approach is safer but costlier to implement and maintain and much harder to design.

Step 3: Choosing the firewall functions and outlining the security policy

Next, we finalize which functions will need to be implemented on the hosts. For example, this includes packet filtering, application proxies, and stateful inspection (also referred to as dynamic packet filter firewalls) to cover various services, from protecting IP addresses and HTTP to DNS. We also work on the security policies and decide on the needed network resources, authorization controls, and access policies.

Step 4: Defining the architecture characteristics

When designing a firewall system, it is important to determine how critical some firewall technology aspects are. For instance, this regards availability, performance, reliability, security, benefits vs. firewall pricing, ease of configuration, simplicity of management, maintenance complexity, and other characteristics.

Step 5: Creating system design documentation

We then put the firewall system design in the form of clear and detailed documentation with workflows and diagrams. It includes environment documentation, notes on the requirements, the appropriate firewall size, which vendor to choose, how to configure the firewall most optimally, how to enforce it, and so on.


Here are a few packages and firewall system design prices OutsourceIT.PRO offers:


1What is the difference between a single-layer and multi-layer firewall architecture?
The difference lies in the setup. In single-layers, there’s only one deployed firewall that defends the network, while multi implies a two or more-layered configuration arrangement. There's also such a thing as two-tier and three-tier firewall architecture, involving combinations of an external firewall, a DMZ, and an internal firewall.
2What happens if you choose the wrong firewall architecture?
The chosen architecture is one of the parts that form the organization’s network security. If you discover that it isn’t optimal after deploy, do-overs will be costly. Similarly, you can end up with lots of “duck tape” that leads to slower performance or possible breaches.
3What are the key firewall design principles?
Thoroughly studying and analyzing the existing environment, outlining the policies logically and simply, and choosing the deployment location are among the main principles. Aligning the firewall system design with the organization’s individual needs and requirements, implementing a layered defense, and making weighted decisions on the optimal vendors of network firewalls are also fundamental.
4What are common challenges in firewall design?
Although challenging, not investigating the existing environment thoroughly can lead to unwanted consequences. Similarly, not planning for future expansion brings scaling issues. It may also be tough to design such a firewall system that won’t harm overall performance due to security matters, as optimization is integral.
5What can be misconfigured as a result of poor firewall system design?
For instance, the quality of packet filtering configuration greatly determines other firewall function decisions. Misconfiguring packet filtering on routers can lead to flaws that may not be compensated by application proxies or stateful inspection. Plus, if your filtering and access control are complex, this can imply immense resource demands. Handling the matter effectively requires in-depth knowledge of the selected platform, the ports and protocols, and a clear understanding of the performance and system requirements.
6When is using a firewall system design service reasonable?
A clear firewall system design forms the basis of effective firewall installation and configuration. If a company lacks the required skills to make such crucial decisions, using the services of professionals with firewall-as-a-service design offers can help you safeguard your system, keep it up to date, cut costs, and ensure you have a modern, safe, future-proof, and scalable network. This is equally important for small businesses and large enterprises.