In this modern era, we can see that the use of the internet is often encountered everyday. Starting from the interests of communication, information or even as a means of entertainment you can find by surfing in cyberspace.
But do you know that besides the many benefits that are on the internet there are quite a number of dangers lurking too, starting from computer viruses ]vulnerable to crime, information breaches and others. To overcome this, the Firewall emerged as a form of component or software that provides security in the use of cyberspace.
If you see the structure of the firewall language can be interpreted as a wall of fire. The use of wall symbols here is true because the main function of a firewall fortifies or gives security to your computer by controlling connections between networks. When the connection is secure, the firewall will give way, vice versa when it is not safe it will be immediately closed.
Types of Firewalls and Their Functions
Because of the many interruptions or problems that arise from using the internet, it is not surprising that there are other types of firewalls. with their respective main functions. There are seven types of firewalls namely Packet Filter, Circuit Level Gateway, Application Level, NAT, Stateful Firewall, and others. We will explain each of these in more detail below:
1. Packet Filter
First is the most simple and widely used firewall, Packet Filter. Equipped with two Network Interface Cards (NICs) and functions to filter (filter) incoming packages. Packet Filter is also commonly referred to as Packet-Filtering Router.
2. Circuit Level Gateway
The next type of firewall is part of the proxy server. Proxy server is a gateway or link between the internet and client computers.
In operation, the Circuit Level Gateway does have higher performance in the OSI reference model than the Packet Filter type and its position is in the Session Layer section. By utilizing modifications from this firewall the user can hide information relating to the protected network even though it does not filter various packages in a connection.
3. Application Level
The next Firewall is Application Level or also called Application Proxy (Gateway). By using this type of firewall the packet will not be allowed to pass directly.
The actual proxy application on the computer will automatically activate the firewall and divert the request into a network that is more private, if indeed information that is received safely then the request is forwarded into a public computer network. It is also considered to have a fairly good level of security.
4. Network Address Translation (NAT)
Next is a type of firewall called the Translatin Network Address or commonly abbreviated as NAT. This type of firewall is able to carry out automatic protection against systems that operate behind a firewall. The purpose of this Network Address Translation is to multiplex network traffic and then send it to WAN, MAN networks or wider network coverage.
As the name implies, the presence of this Network Address Translation gives the impression that the packet is from IP Address. Besides this NAT also automatically creates a table and displays information about the connections found in the firewall. Using this table the user can also map addresses or IP Address of a network to its external base and based on its NAT firewall ports.
5. Stateful Firewall
This one firewall is known to have distinctive features because of its function in combining the various advantages commonly offered by other filtering firewalls, proxy and circuit level in a system.
Before checking the Stateful Firewall always filtering the traffic according to packet characteristics. After filtering, then it can be determined whether the packet is allowed to enter or not.
6. Virtual Firewall
Referring to its name Virtual Firewall is intended as a mention of certain logical firewall that is in a physical device, can be in another computer or firewall. In this Virtual Firewall, there is not only one network, but several networks can get protection with the uniqueness that is the hallmark of Virtual Firewall, namely only by utilizing a device.
When utilizing this Virtual Firewall, an ISP or Internet Service Provider can bring more convenience and security to its customers because their network traffic is always safe.
Besides being more secure the use of a device also provides its own advantages by saving more costs and more efficiency. But unfortunately this type of firewall is only found from the upper classes, for example in the Cisco PIX 535.
7. Transparent Firewall
Finally is the Transparent Firewall which is also commonly called the Bridging Firewall. This firewall is actually not firewall purely but is a derivative of the Statefull Firewal, the type that we discussed earlier.
Transparent Firewall can also do all the workings of Pcket Filtering, just as in the Statefull Firewall. And as the name suggests sometimes this Transparent Firewall is invisible to the user but can provide a fairly good protection.
We have mentioned the types of firewalls and how they work and their advantages. Need to be careful in choosing the right type of firewall according to your needs as an individual or a company with a legal body.
Considering the more important the existing data, the more insecure also because it can be attacked by hackers or crackers. With a firewall it can provide little or perhaps enough protection for your data.