Firewall Configuration: A Useful 4 Step Guide


A firewall is a relatively familiar term, especially for the ones who are using the internet or working in large companies. Sometimes you must have heard someone saying that he can’t access this site because the firewall is not allowing him to do so. No matter if it’s your home or a large establishment, a firewall is something that is providing security to your system from potential hackers and offensive sites.

A firewall primarily functions to monitor incoming and outgoing network traffic and permits or blocks the data as per the set of rules provided. Firewall guards your internal network and the traffic coming from the external source such as the internet so that unwanted incidents like malicious virus attack, hacking etc., can be avoided by keeping away the suspicious messages, not qualifying the security check. It acts as a checkpoint.

There are many ways through which attackers can gain access to your system if it is not protected correctly. Let us look at the following examples

In this article:

A) Firewall Configuration Examples

You can add or remove filters as per your requirements or conditions. It is customizable. Some Firewall configuration examples are:-

  • IP Address- Machines on the internet are provided with unique addresses/numbers which are called IP addresses (e.g.

Domain names – It is difficult to remember the IP address that has multiple numbers compared to a readable name such as Also, The  IP addresses can be changed if required. A company may block or restrict access to specific domain names.

Protocols -– Protocols define how clients and servers will communicate. Some examples of protocols set for firewall filters are Hypertext transfer protocol (HTTP), Internet protocol (IP), File Transfer Protocol ( FTP), etc.

Particular/specific words or phrases – In this, the firewall will search for an exact match., For example, if you can instruct the firewall to block packets containing the word D-Day, packets containing the ‘D Day’ (without hyphen) will not be blocked because they are not the exact match.

There are many ways through which attackers can gain access to your system if it is not protected properly. Some examples are: –

  • Remote Login: In this, a person can gain access and control your computer.
  • Email Bombs: In this, the attacker sends emails thousands of times until your email system cannot accept any more messages.

Other examples include denial of service, viruses, spams, operating system bugs, etc.

B) How to Configure a Firewall

The basic configuration of a Firewall and firewall configuration setup may include the following steps.

Securing  Access– The access to the firewall must be secure with a strong login id and password. Only authorized and trusted users should have access. If any hacker or attackers gains access to your firewall, then you are bound to be in great trouble.

Define/architect firewall– Once you set the access control, identify and categorize the data and group it together. You can create different zones for different sets, for example, sensitive data like bank details, card details, health data can be clubbed together, and workstation, point of sale (POS) devices, etc. can be clubbed together. The safety will rise with the increase in zones. The more zones you have, the more secure you are. Once your network zone structure is designed, and a corresponding IP address is established, then you are ready to create your firewall zones and assign them to your firewall.

●    Configure access control/Firewall– After you set your network zones and assigned them to interfaces, you have to  decide which traffic you want to allow to flow in and out of these specified zones. Access control lists (ACL) are the firewall rules or set of rules which will permit the traffic and allow/control the access of different zones. 

Configuring other firewall services and loggings– If your firewall is capable of acting as a dynamic host configuration protocol (DHCP) server and Intrusion prevention system (IPS) etc., then you should configure the service you intend to choose and make sure to disable all the extra services which you don’t want to use.

●    Firewall configuration testing- Now it is time to test your firewall configuration. This will verify whether the firewall is blocking the traffic, which is supposed to be blocked by the Access control list(ACL). Penetration testing and vulnerability, testing should be implemented.

●    Firewall configuration management- You require proper firewall configuration management not only to look after your firewall but also to maintain and monitor firewall configuration standards and recommend if any updates or changes are needed from time to time. Apart from keeping the logs and other details regularly, an audit must be conducted at a regular interval of time. 

C) How to Create a Firewall

These are some basic steps that can help you to create a firewall.

First of all, you have to create  your firewall-name.

● You must define at least one rule before creating . When you create a cloud firewall, there are four outbound and inbound rules defined by default, and consequently, some fundamental traffic is allowed. You can keep, modify, delete, or can make new ones.

● Default Inbound rules- SSH.

● Default outbound rules.

● Apply droplets.

● Create a firewall.

D) How to Use a Firewall

Generally, one of these methods is used to control the outgoing and incoming traffic.

  • Packet Filtering- A set of filters analysis packets, which are chunks of data.,  Only the data which passes through these filters will proceed further to the requested system, the rest of the other data will be discarded.

Proxy service– In this case, information is retrieved from the internet by the firewall and then sent to the requested system and vice versa.

● Stateful inspections- This is how the firewall doesn’t examine the whole packet (a chunk of data) but instead it compares some critical parts of the packet to a database of trusted information. Some specific defining characteristics of the data/information traveling from inside the firewall to the outside are monitored. Then incoming information is compared to these characteristics, and if the comparison matches reasonably, then it is allowed else, it is discarded.


Firewall configuration on network security is essential as it provides safety against unwanted and unauthorized access. The firewall is inserted in between the user network and the internet so that a controlled link can be established. There are firewall configuration standards that must be maintained and followed by the users. Hackers and attackers are using modern and advanced technology to interfere with the smooth running of your establishment to extract their benefits. Required firewall installation and configuration will definitely minimize this threat.

Modernization has also brought new opportunities for criminals and attackers, and they keep updating themselves accordingly. In order to steer clear of this ever-evolving state of online fraud, individuals and companies using the internet must have the right firewall configuration in place, to protect the data and other valuable information going into the wrong hands. This firewall must be updated and modified according to the demand and should also be managed by professionals. To know more about courses, UNext Certificate and Courses can give you the right course to turn to.

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