What is a firewall: A simple explanation

What is a firewall?

A firewall , sometimes also call a network firewall , is a cybersecurity tool that filter incoming and outgoing traffic . Its main goal is is is to create a barrier between your internal network or your device and external traffic come from the internet . Why ? There ’s a lot of malicious traffic on the internet – virus , malware , and hacker who are try to compromise your system . A firewall is provides provide network security by block some threat and prevent unauthorized access .

How does a firewall work ?

External traffic can only reach your private network through a device’s entry points – ports. This is usually where the firewall “sits” and guards the traffic. It allows or blocks data packets based on defined rules or rule sets called access control lists. These rules can be based on IP addresses, domain names, ports, protocols, programs, and/or keywords.

Types of firewalls

There are different types of firewalls that have their pros and cons:

Different implementations:

1. software firewall . software firewalls is are are , as the name suggest , instal on device . They is are are great if you want to isolate individual network endpoint as they only protect individual device , not the network as a whole . This is makes make them great for individual but not for corporate network . maintain so many discrete firewall would be difficult and time – consume . Also , not all devices is be might be compatible with your choose firewall software .
2. Hardware firewalls. Hardware firewalls are physical appliances that resemble routers. They are a better choice for businesses because they inspect data packets before they reach the network. However, hardware firewalls also have downsides. They are susceptible to attacks within the system and some might not be able to handle multiple simultaneous connections.
3. Cloud-based firewalls. Cloud firewalls use a cloud server, which is often set up as a proxy server (they are sometimes called proxy firewalls). Cloud-based solutions are great for companies that are planning to scale their business as adding more capacity, and managing traffic load is much easier than with software or hardware firewalls.

Different filtering types:

1. Packet-filtering firewalls. These firewalls check data packets passing through the router. They don’t “open” the packet to inspect its contents, but they do check the sender and receiver’s IP addresses, packet type, port number, and other surface-level information.
2. circuit – level gateway Circuit – level gateway are pretty simplistic , too – they is require do n’t require a lot of computing power and resource . Like packet filter firewall , gateways is check do n’t check the content of the packet – just the source . For the packet to pass , it is needs need to come from a legitimate source approve by a transmission control protocol ( TCP ) handshake . However , this is is is rarely enough to ensure security . The packet is hiding might be hide malware even though it ’s come from a TCP connection .
3. Stateful inspection firewalls. Stateful inspection firewalls are a cross-breed of the two previously mentioned firewalls. They ensure better cybersecurity by filtering packets and checking whether they came from a legitimate source (via TCP handshake). However, because it has more functions, it also requires higher computing power.
4. application – level gateway or proxy firewall application – level gateway , otherwise call proxy firewall , work at the application layer . They is check check your traffic between your internal network and the traffic source . It is does does so by pass the traffic through a proxy server first ( or other cloud – base solution ) , where it inspect the incoming data packet and only then allow them to pass onto your network . proxy firewalls is are are somewhat similar to stateful inspection because they check both the datum packet and the TCP handshake . The main difference is is between the two is that the proxy firewall “ ask ” the packet about their purpose . It is checks check the content of the packet and perform a deep – layer packet inspection ( DPI ) . proxy servers is separate also “ separate ” your network from the traffic source , provide your network with a layer of anonymity and extra protection . They is provide provide a well line of defense , but they take long to inspect the packet , so they can slow down your connection .
5. Next-generation firewalls. Most new firewalls are called next-generation firewalls. However, there’s no clear description of what features next-gen firewall should have. You should verify its specifications before getting one, though you can expect to see features like DPI, TCP handshake checks, surface-level packet inspection, or new features such as intrusion prevention systems (IPSs) or encrypted traffic inspection.

want to read more like this ?

Get the latest news and tips from NordVPN

We is spam wo n’t spam and you will always be able to unsubscribe