What is a firewall and how does it work in computer networking?

A network firewall is a gatekeeper for your computer or network. It checks all incoming and outgoing traffic to make sure it's safe. It's like a bouncer at a club who only lets people in if they're on the guest list. Imagine your house as a network and your front door as a firewall. The firewall only lets people in that you know and trust. It keeps out strangers and bad guys.

Selon moi un par-feu dans un réseau informatique est un tamis qui sert à filtrer les différentes types de connexion qui entre ou qui sortent d'un réseau informatique. Cela crée une zone démilitarisée qui est un point crucial pour la sécurité d'un réseau. Autrement dit c'est à ce point que toutes connexions qui peuvent rendre vulnérables un réseau sont bloquées.

A Network Firewall is the most important component when it comes to security for your computers, severs and network. It allows for monitoring of incoming and outgoing traffic based on rules or policies that align with the best security practices. There are two main types of firewalls: Host-based software which is present on all versions of Windows and physical hardware appliances, such as those from Cisco that perform the same operations but at much larger scale, protecting massive corporate networks.

A firewall is a crucial security component in computer networks. Acting as a barrier between trusted internal systems and external networks, it monitors and controls data traffic based on preset rules. By examining incoming and outgoing data packets, it filters them using criteria like IP addresses, ports, and protocols. This scrutiny prevents unauthorized access, malicious attacks, and potential threats from compromising network security. Essentially, firewalls work as gatekeepers, allowing safe data passage while blocking or filtering out potentially harmful traffic, enhancing overall network safety.

A firewall allows us to protect and control our company's network, reducing user bandwidth consumption, protecting company information and, above all, the information of each mobile user when using the network.

Firewalls uses various techniques to enforce security policies, including packet filtering, stateful inspection, and application-level gateways. Packet filtering examines packet headers and filters them based on predefined rules, such as allowing or blocking specific IP addresses or ports.

For security reasons one needs a firewall to best protect, understand and maintain incoming and outgoing internet data traffic. Based on each setup or firewall rules, certain connections or devices can be blocked 🚫 from accessing local or international traffic capabilities for security reasons. Furthermore; The rules are based on the firewall's policy, which defines what kind of traffic is allowed or denied. Firewalls can use different methods to inspect the packets, such as packet filtering, stateful inspection, proxy service, or deep packet inspection. So ultimately firewall in networks is major security features which ensures the entire network is secure and safe for all users and while ensuring hackers don’t get through.

An organization's previously defined security rules are used as the basis for the monitoring and filtering of incoming and outgoing network traffic by a firewall, a network security device. A firewall is essentially the wall that separates a private internal network from the open Internet at its most basic level.

Firewall work by examining data packets and determining whether to allow or block them based on the configured rules. Commonly, firewalls use a combination of packet filtering, proxy services, and stateful inspection to assess and control traffic. They help prevent unauthorized access, protect against cyber threats and extablish a secure boundary for a computer network.

fonctionne sur le principe du filtrage simple de paquets Il analyse les en-têtes de chaque paquet de données (datagramme) échangé entre une machine du réseau interne et une machine extérieure.

Le filtrage s'effectue en fonction des informations habituellement trouvées dans l'en-tête des paquets IP [4] : les numéros de protocole ; les adresses IP source et/ou destination ; les numéros des ports source et/ou destination, qui sont intégrés dans le message TCP ou UDP (User Datagram Protocol) ;

une fonction de sécurité qui rejette les paquets ARP non valides et malveillants. Cette fonction empêche une classe d'attaques de l'homme du milieu, où une station malveillante intercepte le trafic pour d'autres stations en empoisonnant les caches ARP de ses voisins peu méfiants.

To configure a firewall, you will need the default ip address of the firewall to access the web interface of the firewall. Upon logging into the web interface, and change the firewall's ip address to align with the network. rom their, you can controll access control lists to begin allowing/disallowing traffic to the network.

When comparing a firewall to a router, the general rule of thumb from my experience, is that routers by default allow traffic to pass through the network, while a firewall does the opposite.