A firewall is quite a 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 it is a large establishment, a firewall is something that is providing security to your system from potential hackers and offensive sites. In this article let us look into Firewall Configuration.

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 doubtful messages that do not qualify the security check. It basically acts as a checkpoint.

In this article:

  1. Firewall Configuration Examples
  2. How to Configure a Firewall
  3. How to Create a Firewall
  4. How to Use a Firewall

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 such as
  • Domain Names- It is difficult to remember the IP address that has multiple numbers compare to a readable name such as The other thing is IP address can be changed if required. A company may block or restrict access to specific domain names.
  • Protocols- Protocols are simply defined as how clients and servers will have conversations. Some examples of protocols that are being 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 the packet with the word D-Day in it. In this case, D Day like this will be allowed but D-Day with a hyphen will not as this is 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.
  • Denial of service
  • Viruses
  • Spam
  • 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 the Access- The access to the firewall must be secure with strong logins and passwords. Only authorized and trusted persons should have access. If any hacker or attackers gains access to your firewall then you are in big 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 club together. The safety will increase with the increase in zones. The more zones you have, the more secure you are.

Once your network zone structure is designed and you have established a corresponding IP address 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, now it is the time to decide which traffic you want to allow to flow in and out of these specified zones. Access control list (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 the name of your firewall.
  • You must define at least one rule before you can create it. When you create a cloud firewall, there are four outbound and inbound rules defined by default and because of that some fundamental traffic is allowed and 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 analyses packets, which are chunks of data, and 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 the method in which the firewall doesn’t examine the whole packet (a chunk of data) but instead it compares some key 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 the information is allowed else it is discarded.


Firewall configuration on network security is very important 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 advance 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 ways to the criminals and attackers and they do keep on updating themselves accordingly. In order to keep from 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 hand. This firewall must be updated and modify according to the demand and should be managed by the professionals. 

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