Questions What do you mean by Network?

What do you mean by TCP and UDP?

Ports for both TCP and UDP are used to allow servers to set up listeners for particular types of traffic. The services file on your computer has a list of well-known ports. So if a client sends traffic on port 80, for example, the server will treat it as unencrypted http traffic. There are ports for dns, telnet, dhcp, and many other services.

12. 
    What do you mean by a Firewall?
    

A firewall is a software program or a hardware device that acts as a filter for the data entering and leaving the network. The firewall can be analogous to the security guards who have control over who can enter or leave a building. A firewall reduces the risk and threat from the malicious packets that are travelling over the public network and can hamper the security of a private network.

13. How does a Firewall work?

A firewall acts as a border between your computer and the connected network(like LAN or internet). It inspects all the incoming and outgoing packets of the network. It inspects on the basis of programmed rules which are created by humans. These rules may depend on the demand, necessity and security policies defined by the organization. These rules will tell whether a packet will be allowed by the network barrier or not. If any packet is identified as a danger or threat according to the defined rules then it will not be allowed through the network. Though there are many rules and policies, the firewall also defines some default policies. It consists of three actions.