$8.$

Question $8$

Many firewalls block ports, meaning that they prevent either incoming and$/$or outgoing network traffic on particular port numbers.

How could this help against botnet attacks?

$1$ point

It would protect a valuable server by ensuring that external computers are not able to send packets to it directly, so malicious attackers are never aware of the server itself, or know its IP address, or other features of the internal network.

It would prevent the botnet using a particular type of server application to communicate with the outside world. For example, running an email server and sending spam

It would make it possible to check each packet coming into or out of a machine or network to see if it is infected by the botnet, or otherwise contains malicious data

It can stop a denial of service attack in which packets are sent for applications that are not running on a machine and are therefore not detected, but can still clog up the network

It can prevent the botnet from communicating with, or attacking particular web servers, for example targeting a particular bank for ransom