Firewalls

A firewall is a software 

It is a computer network security system that restricts internet traffic in, out, or within a private network 

It is typically intended to prevent anyone inside or outside a private network, from engaging in unauthorized web activities and to help prevent malicious activity 

The term comes from the concept of physical walls being barriers to slow the spread of fire until emergency services can extinguish it 

A firewall acts as a barrier or filter between your computer and another network. It creates a safety barrier between a private network and the public internet. A firewall is especially important to large organizations 

A network firewall and a structure firewall work in a similar way 

It works by filtering the incoming network data and determines by its rules if it is allowed to enter a network. These rules are also known as an access control list. These rules are customizable and are determined by the network administrator. The administrator decides not only what can enter a network, but also what can leave a network. These rules either allow or deny permission 

Firewall rules can be based on:

IP addresses (when it recognizes IP addresses, it blocks them) 

Domain names 

Protocols

Programs

Ports 

Keywords 

Firewall types:

1. Host-based firewall (software firewall that is installed on a PC, only protects that computer only)

2. Network-based firewall (combination of hardware and software, protects an entire network)

An IP address is an assigned unique identification code assigned to all the devices in the network 

Any traffic that doesn't meet the criteria is filtered and stopped 

Criteria include a padlock, domain name, https, and keywords

A firewall is a protective shield which allows a user to block unwanted data from their network 

https://www.howtogeek.com/144269/htg-explains-what-firewalls-actually-do/

Notes taken in the class of Miss Shaista Shahab (2022)