Firewalls

In simple terms, the firewall is a component that is responsible for monitoring and controlling the incoming and outgoing traffic depending on the rules configured.

If we look into a cloud environment, such as AWS, they provide firewall functionality through a security group, which is attached to each EC2 instance and through NACL, which is attached to an entire subnet.

How a firewall works?

The firewall acts as the front end for receiving packets from remote servers. Whenever a request comes, it is first received at the firewall end:

The firewall will check its Rule table to see if a particular IP is allowed to connect to the remote Server on the specified Port.

If the rule is Allow, then the firewall will allow...