How firewalls control the in and out flowing traffic of the network?

A firewall can be represented as a special type of network security device or a software program that monitors and filters incoming and outgoing network traffic based on a represented group of security rules. It facilitate as a barrier between internal private networks and external sources (including the public Internet).

The objective of a firewall is to enable non-threatening traffic and prevent malicious or unwanted data traffic for securing the computer from viruses and attacks. A firewall is a cybersecurity tool that filters network traffic and provide users block malicious application from accessing the web in infected computers.

Firewalls can be executed in both hardware and software. Firewalls are generally used to prevent unauthorized Internet users from accessing private networks connected to the Internet, particularly intranets. All messages entering or leaving the intranet move through the firewall, which determines each message and blocks those that do not meet the specified security element.

Firewalls use various methods to control traffic flowing in and out of the network which are as follows −

  • Packet filtering − Packet filtering is “controlling access to a network by analyzing the incoming and outgoing packets and letting them move or halting them depends on the IP address of the source and destination. Packet filtering is one approach, among many, for performing security firewalls.

    Packet filtering is both a tool and a technique that is a basic building structure of network security. It is a tool in that it is an instrument that aids in accomplishing a service. It is an approach because it is a method of accomplishing a task.

    Packets (small chunks of record) are analyzed against a group of filters. Packets that create it through the filters are sent to the requesting system and some others are discarded.

  • Proxy service − The proxy service firewall is a system that can provide protect the network security by filtering messages at the application layer. It essentially serves as a gateway or middle man between the inside network and outside servers on the web. It is also known as a gateway firewall, it is more secure in its need of stateful and deep packet inspection technology to analyze incoming traffic.

  • Stateful inspection − Where static filtering determines the packet headers, stateful inspection firewalls examine a several elements of each data packet and compare them to a database of trusted data. These elements contains source and destination IP addresses, ports, and applications. Incoming data packets are needed to sufficiently match the trusted data to be allowed through the firewall. Stateful inspection is a latest approach of firewall filtering.

    A current approach that doesn’t examine the contents of each packet but instead compares certain key elements of the packet to a database of trusted data.

Updated on: 10-Mar-2022


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