Internet Security Firewall – What is Firewall & How Does Firewall Works


Internet Security Firewall, especially Next Generation Firewalls focus on blocking malware and application-layer attacks or threats. It is integrated with an Intrusion Prevention System (IPS), and are able to react fast and seamlessly to detect and fight attacks across the network.

Internet Security Firewall

Firewalls can act on past set policies to protect users’ network, and carry out a quick assessment to detect invasive or suspicious activities like malwares. Not only does it detect these malwares, it also shut it down. By utilizing a firewall for your security infrastructure, you are setting up your network with policies to allow or block incoming or outgoing traffic.

Internet Security Firewall

Firewall helps to establish a barrier between users’ internal network and incoming traffic from external sources like the internet. This operation is done in order to block malicious traffic like viruses and cyber hackers.

What is a Firewall?

A firewall is a network security device that helps to monitor and filter incoming and outgoing network traffic as with an organization’s previously establishment security policies. Basically, a firewall is an essential barrier that sits between a private internal network and the global internet. The main purpose of the firewall is to let non-threatening traffic in and keep out dangerous traffic out.

Importance of Firewall

It also performs the basic network level functions like Network Address Translation (NAT) and Virtual Private Network (VPN). NAT hides or translates internal client or server IP addresses that are in a private address range as defined in RFC 1918 to a public IP address.

Hiding the addresses of protected devices preserves the various number of IPv4 addresses. And it is a defense against network reconnaissance since the IP address is already hidden from the internet.

How Firewall Works

Internet Security Firewall analyze incoming traffic based on pre-established set rules and it filter traffic coming from unsecured or suspicious sources to prevent attacks and viruses. It guards the traffic at a computer’s entry point, called ports. This is where information is exchanged with external devices.

For example, think of an IP address as a house, and port numbers as rooms within the house. Only trusted people (source addresses) are allowed into the house (destination address). It also provides filters so that people in the house are not allowed to access certain rooms (destination ports), depending on if they are the owner of the house, a child, or a guest. The owner of the house is allowed to any room (any port), while the children and guests are only allowed into some set of rooms (specific ports).

Types of Firewalls

There are basically four types of firewalls. Below are the types of firewalls and what they mean:

Next Generation Firewalls (NGFW)

This firewall combines traditional firewall technology with additional functionality like encrypted traffic inspection, intrusion prevention system, anti-virus, etc. It also includes a Deep Packet Inspection (DPI). The DPI examines data within the packet itself, enabling users to identify, categorize, or stop packet with malicious data more effectively.

Proxy Firewalls

This filter network traffic at the application level. The proxy acts as an intermediary between two end systems. Client must send a request to this firewall where it is, then evaluated against a set of security rules, and then permitted or blocked. Additionally, it monitors traffic for layer 7 protocols like HTTP and FTP. And uses both stateful and deep packet inspection to detect malicious traffics.

Network Address Translation (NAT) Firewalls

It allows multiple devices with an independent network address to connect to the internet with a single IP address. Hereby keeping individual IP address hidden. As a result, attacks scanning a network for IP addresses cannot capture the details, proving a greater security against attacks. This firewall is similar to proxy firewalls as they act as an intermediary between a group of computer and outside traffic source.

Stateful Multilayer Inspection (SMLI) Firewalls

This firewall filters packets at the network, transport, and application layers. And compare them against trusted packets that are known. Similar to NGFW, this also examines the entire packet. And only allow them to pass if they pass each layer individually. It examines packets to determine the state of the communication to ensure all communications is taking place within trusted sources.


Please enter your comment!
Please enter your name here