Review about Firewall

Definition of Firewall

The definition itself is a security system whose job is to protect your computer from various threats on the internet network. This security system works like a wall that limits the network on a computer. With this “firewall” you can limit data traffic, information, and activities on a computer network.

This security system is divided into two types, namely hardware and software. These two security systems have different settings and configurations. However, the function remains the same, namely protecting network security.

Usually, we often find software-based security systems that are widely used as a security system for home internet users. Usually, this security system is added with anti-virus assistance to make it more secure. This type of security system protects both inbound and outbound traffic.

Firewall Function

Using a firewall in the world of computer networks is mandatory. Where it is important we know what the function of this security system is and what its duties are along with a full explanation.

Protecting Data from Hackers and Unauthorized Users

As an internal data barrier with wide network access. Because of this security system, hackers and foreign users cannot access the data on your computer. If the computer does not have a security system, the data on that computer is very vulnerable to being hacked and stolen.

Blocking Unwanted Messages

Sometimes some people are not responsible for trying to send a computer virus in the form of a message sent to you. Usually, this message is sent via email if you click it then a program is installed accidentally and makes your computer suddenly shut down.

This will not happen if you activate the security system on the computer. So that messages that should be blocked automatically by the security system are free to be sent to your email inbox.

Blocking Unwanted Content

Apart from blocking messages that contain viruses, this system can also block websites or content from certain website addresses. You can set it manually so that access to the website is not allowed.

Making Online Games Safer and More Comfortable

Playing online games also comes with risks. Where this online gaming network is also vulnerable to hacking irresponsible people.

By utilizing a Firewall, unused ports will be closed by the security system so that hackers cannot use them to send viruses to you.

Bandwidth Monitor

A firewall Can also be used for bandwidth monitoring and limit the internet speed that will be used.

For example, bandwidth usage is prioritized for business so that the bandwidth used for content such as music, videos will be reduced.

Accessing VPN services

A firewall Can also be used to facilitate VPN or Virtual Private Network connections. By using a VPN service, your internet network access will be safer.

With a VPN you can access blocked sites. So that with the help of this security system will help secure you from unwanted viruses.

How a Firewall Works

This firewall works like a filter, where this filter is useful for filtering data on the network on the internet. You can set the data that is allowed or not be accessed by the computer yourself.

There are three ways the filter works in a security system in securing this network, here is a complete explanation.

Packet filtering or stateless

firewalls have their own rules to see whether or not data access to the network is allowed. Each data packet is checked independently and is isolated if the packets are sent individually.

If the data packet is considered dangerous, it will not be allowed to enter. Conversely, if it is safe, the data will be forwarded into the system.

Proxy service

This application works as a liaison between computer networks. Proxy applications are located in the security system and are responsible for examining the data packets exchanged in the network.

Stateful inspection

This system can trace data packets received by the previous activity. The package received is then checked into the packet database. Whether the package is positive or does not represent a risk of harm, it will be forwarded to the requested system.

Types of Firewalls

Choosing a firewall is a bit of a dilemma because we are still confused about choosing a security system that suits our needs. Each security system certainly has its features and configurations. So we have to know what types of computer security systems are on your computer.

Security systems on computers are generally divided into categories based on their general structure and method of operation. Here are 8 types of firewalls that you need to know.

Packet-Filtering Firewall

Packet-Filtering Firewall is a security mechanism that blocks network data packets that are carried out based on the rules previously set by the user.

With this security technology, it is the oldest security system that sorts data packets that are allowed to enter and data that is blocked. This computer security system checks the data packets that are on the router or switch traffic.

The data that is checked include packet type, port number, IP address, and surface-level information without opening the data packet. If the packet does not pass the check, it is discarded.

The advantage of Packet-Filtering Firewall is that it does not require too many resources so that it does not overload your computer’s performance. The drawback is that it has a fairly outdated technology compared to today’s computer security systems.

Circuit-Level Gateway

Lever Circuit This Is a fairly simple type of security system that is intended to work easily and quickly approve or reject traffic, without using significant computational resources.

The main function of the Circuit Level Gateway Firewall is to verify the Transmission Control Protocol (TCP). TCP checks are designed to ensure that the session of the packet is valid or secure.

Even though it has few resources, it cannot check incoming and outgoing packets. So if there is malware but it escapes within the TCP handshake then the packet still passes so this security system is not suitable for business.

Stateful Inspection Firewall

Stateful Inspection Firewall is a network whose job is to track the characteristics and operating conditions of the network. This Stateful Inspection Firewall is configured to distinguish good and proper network packets across different types of connections.

This security system combines TCP packet inspection and handshake verification technology for a higher level of protection.

But the drawback of this security system requires more computational resources. And it can slow down the transfer of legitimate packets when compared to other security systems.

Proxy Firewall

Proxy Firewall is similar to Application-Level Gateway or Cloud Firewall types. Proxy Firewalls operate at the application layer to sort incoming traffic between networks by network traffic sources. This is why it is called an Application-Level Gateway or application-level bridge.

This security system is delivered via a cloud-based solution or another proxy device. So as not to let traffic connect directly, this proxy security system will first make a connection to the traffic source and check the incoming data packet so that it is properly filtered.

In short, this Firewall proxy creates an extra layer of separation between the client and individual devices on your network. This computer security system provides additional protection for anonymous networks.

Of course, this multi-layered security system can significantly delay the transmission of computer networks.

Next-Generation Firewall

From the name alone, it is very clear that the Firewall is a new generation. Its features are quite comprehensive ranging from internal packet inspection, TCP handshake inspection, and surface-level packet inspection.

Another computer security system technology is the intrusion prevention system or IPS. IPS is an intrusion prevention system that functions to stop attacks on your network automatically and fix the problem.

Firewall software is

often considered an antivirus. The difference is that a computer security system can control network traffic in a system that acts as a filter for incoming traffic. Meanwhile, antivirus protects the system from internal attacks by looking for malicious files and then deleting them.

This one software includes all types of computer security systems installed on the device. The benefits of this type can create deep protection by isolating the network from both directions.

The downside of this computer security system is that maintaining software on different devices can be difficult and time-consuming.

Hardware Firewall

Is a type of computer security system that has a physical form in the form of a device that works like a router. The way it works is to intercept data packets and traffic requests before they are connected to the network.

Cloud Firewall

The last one is a cloud Firewall or Firewall-as-a-Service (FaaS). This computer security system is considered to be similar to a proxy. Because cloud servers are used in proxy settings. However, proxies are not always in the cloud.

Mikrotik Firewall

Operates by using rules. Each rule consists of a two-part matcher which corresponds to the traffic flow against the given conditions and measures whether the existing packet is suitable or not.

Filtering rules are grouped in a chain. So that packets are matched under one common criterion in one chain, and then passed for processing against some other common criterion for the other chain.

The sample data packet must match the IP address and port, of course, this can be done by adding some rules with the IP address and port according to the chain forward.

But the best way is to add one rule that matches traffic from a specific IP address, for example, filter / IP add src-address = jump-target = “chain”.

NAT Firewall Functions In Mikrotik

NAT or Network Address Translation is a computer security system feature that functions to change the IP address to the sender who will be sent to the internet.

Technically, this NAT changes the data packets originating from the user’s computer as if they came from a router.

SRC-NAT And Masquerade

Firewall NAT consists of several commands such as src-nat and masquerades which can hide the local IP and replace it with the public IP already installed on the router.

  • SRC-NAT, this command can change and at the same time choose the public IP address used.
  • Masquerade, will automatically replace the IP address on the public interface. Can simplify the installation and use a dynamic IP address, for example, DHCP, PPTP, or VoIP

Dst-Nat. And Redirect

This command is used to change the destination IP address or direct the connection to localhost.

  • Dst-nat can change the IP address and destination port of a particular connection.
  • Redirect, can redirect the connection that was through the router to be redirected to localhost.

Mikrotik Firewall Settings

In configuring or setting the Firewall on Mikrotik can be done in several easy-to-understand steps.

For example in Mikrotik with interfaces called LAN and WAN. The WAN IP address is and the LAN IP address is

To start the configuration, we can select menu: IP> Firewall, then we can add settings as needed.

How to Block Sites with Mikrotik Firewall

Blocking a site using a computer security system on Mikrotik is quite easy, you can follow the steps below.

  • Create new Firewall rules, on the menu General, select Chain: Forward.
  • Then determine the IP address of the website that we want to block, for example, with Public IP:
  • Out interface: WAN.
  • On the menu Action select Drop.

The explanation of the configuration above is that if there is a computer from the LAN network that wants to access the website with IP with Outgoing via the WAN interface, the connection will be dropped or blocked by Mikrotik.

Filter Rule Mikrotik Firewall

A filter rule is a rule or policy used to allow traffic to existing in the network, identical to Accept or drop. On the Firewall> Filter Rules menu, there are 3 types of chains available, along with an explanation.

  • Input, this chain is used to process packets that enter the router through an interface with the destination IP address which is one router address. The chain input is useful for limiting configuration access on the Mikrotik router.
  • Forward, this chain is used to process data packets passing through the router.
  • Output, the chain used to process data packets originating from the router and leaving through one of the interfaces.

In chain processing, rules that are taken from the chain according to a list of orders will be executed from top to bottom. If the packet matches a rule, certain actions will be performed on it and no more rules will be processed in the chain. If the packages do not match, they will be accepted.

How to Turn Off a Firewall A

a firewall does have benefits for protecting the network on your computer. But not always this computer security system has positive things, it turns out that there are also negative sides, for example causing conflicts with the default computer security system from other hardware.

Therefore you can turn off the default computer security system from an operating system such as Windows OS.

How to turn off the Windows 7 firewall

How to turn it off in Windows 7 is quite easy, following the steps.

  • Click the button Windows at the bottom left of the screen then search Programs And Files type “Windows Firewall”.
  • In the search section, the Windows Firewall menu will appear.
  • When the Windows Firewall window appears select it and click the link Turn Windows Firewall On Or Off.
  • To disable it from all types of networks, either private or public, you can click the radio button labeled Turn off Windows Firewall (not recommended) then OK.

How to Turn Off Windows 8 Firewall

To turn it off Windows 8 is not too different from the Windows 7 computer security system.

  • Select Start Menu> Control Panel> System & Security.
  • This program has the names Windows Firewall and Windows Defender Firewall.
  • Select Windows Firewall.
  • Turn Windows Firewall on or off.
  • Select Turn off the firewall (not recommended) then OK.

How to turn off the Windows 10 firewall

in Windows 10 turning off the computer security system is also easier as below.

  • Press Windows key + R on your keyboard, then type Firewall.cpl and press Enter.
  • Click the Turn Windows Defender Firewall On or OFF menu.
  • select Turn off Windows Defender Firewall (not recommended) on any network either private or public then click OK.


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