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Subject Enrichment
                          Video Session                                                                  Communication


                     Scan the QR code or visit the following link to watch the video: How a DNS Server (Domain Name System) works
                     https://www.youtube.com/watch?v=mpQZVYPuDGU
                     Now answer the following questions:
                     1.  Can a website be opened through its IP address also?                                (Yes/No)

                     2.  DNS works like a ....................................................................................................................................................... .
                     3.  Who is the resolver server?
                         .....................................................................................................................................................................................




                   1.10 NETWORK THREATS AND SECURITY MEASURES
                 The increased usage of the network for data access and resource sharing has made security a top priority. The Internet
                 is an unsecured channel for transmitting information, posing a high risk of infiltration or fraud from phishing, viruses,
                 trojans, worms, and other malicious software. Let us understand what each of these terms means.

                 Malwares
                 Malware refers to malicious software that are meant to disrupt normal system functionality by inflicting harm to the
                 system, or to gain unauthorised access to the system, or to prevent legitimate users of computer resources access.
                 A virus, worm, or Trojan horse are examples of malware.


                                                                 Malware






                                Trojan Horse                       Virus                          Worm

                 Virus
                 A virus is a piece of software that can damage your computer by overwriting or corrupting system files. A computer
                 virus works in the same way that viruses do in our bodies, replicating and affecting body cells. The infected area refers
                 to the affected area. A computer virus can produce multiple copies of itself by inserting its code into system programs,
                 files, or the boot sector of hard drives, corrupting them in the process. Viruses like boot sector viruses, file infector
                 viruses, and macro viruses cause the system to slow down or even stop working.
                 Worm

                 A worm is frequently sent through a network, and it automatically creates several copies of itself on the hard disc,
                 flooding it. When an email attachment contains a worm, it is automatically transmitted to the recipients, causing
                 network congestion. As a result, a worm has the potential to bring down the entire system and network. Worms do
                 not require a host application to replicate themselves, e.g. In less than 9 hours, the Code Red Worm can create over
                 2,50,000 copies of itself.

                 Trojan Horse
                 A Trojan Horse is a piece of software that appears to be beneficial and desirable but actually causes harm to the system. A
                 Trojan horse can disguise itself as a legitimate application. It might be attached to any game downloaded from the Internet,
                 for example. When such a programme is run, it opens a backdoor in the system, allowing a hacker to get access. All action
                 on the system can be monitored by the hacker. He can also take control of the infected system by destroying its data.

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