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Computer Networks, &, Network Devices
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Identification of Nodes in a, Networked Communications, • A node within a computer network is defined as, a connecting point or, redistributed point or communicating point or joint, or a transfer point, where the data can be stored, received, transmitted, or created., • A node can be either a computer or any device that involves receiving, and sending the data inside the computer networks. It is simply called a, network node., • The link that connects the node of a network is known as a, communication channel.
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Types of Network Nodes, End Nodes, • These are referred to as the initial point or an endpoint for, communication., • Examples of end nodes are computers, security cameras,, printers, and many more., Intermediary Nodes, • The nodes are located in between the initial (starting), point or an endpoint of the end nodes of the computer, network., • Examples of intermediary nodes are bridges, routers,, switches, cell towers, etc.
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Data Communications, • The network nodes are the physical devices that are located in between, DTE (data terminal equipment) and data communication circuits. Bridges,, switches, hubs, and modems are included to execute the conversion of, signals, line clocks, and coding., • Internet and intranet network nodes: these types of nodes are nothing, but host computers, which are identified by an IP address., • Some of the data link layer devices and WLAN access points don’t contain, any IP address and they are referred to as physical network nodes or LAN, nodes., • LAN and WAN network nodes: these types of network nodes are the, physical devices that are involved in performing particular functions and, also every node contains a specific MAC address for NIC (network, interface card)., • The examples are modems, access points of WLAN, and PCs., Continue....
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Telecommunication Nodes, • These types of nodes in fixed telephone networks might be private or, public to exchange the information or a computer that provides intelligent, network service., • While in cellular networks or mobile networks, include base station, controllers to control multiple base stations. Since the cellular network, base stations are not referred to as nodes., Cable TV Network Nodes, , • These types of nodes are related to fiber optic cables, which connect, businesses, homes distributed by common fiber optic receivers within a, specified geographical location., • The fiber optic node in cable systems determines the number of, businesses and homes are connected by a particular fiber node., Distributed Network Nodes, • These types of nodes are servers, clients, and peers., • In distributed networks, some virtual nodes are used to maintain data, transparency.
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Internet, • The Internet is a global network comprised of, smaller networks that are interconnected, using standardized communication protocols., • The Internet standards describe a framework, known as the Internet protocol suite., • This model divides methods into a layered, system of protocols.
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These layers are as follows:, • Application layer (highest) – concerned with, the data(URL, type, etc.). This is where HTTP,, HTTPS, etc., comes in., • Transport layer – responsible for end-to-end, communication over a network., • Network layer – provides data route.
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• The internet is a global network of billions of, servers, computers, and other hardware devices., • Each device can connect with any other device as, long as both are connected to the internet using a, valid IP address., • The internet makes the information sharing, system known as the web possible., • When data is transferred over the internet, it’s, delivered in messages and packets., • Data sent over the internet is called a message,, but before messages get sent, they’re broken up, into tinier parts called packets.
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• These messages and packets travel from, one source to the next using Internet, Protocol (IP) and Transport Control, Protocol (TCP)., • IP is a system of rules that govern how, information is sent from one computer to, another computer over an internet, connection., • Using a numerical address (IP Address), the IP system receives further, , instructions on how the data should, be transferred.
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Web and Internet of things, • The Internet, linking your computer to other, computers around the world, is a way of transporting, content., • The Web is software that lets you use that content…or, contribute your own., • The Web, running on the mostly invisible Internet, is, what you see and click on in your computer’s, browser., , Web
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A collection of information accessed, through the internet., • Information travels primarily through HTTP., • Uses browsers to access documents and web pages., • Navigation to other pages occurs through hyperlinks., • The web consists of digital documents, referred to as, web pages, that are viewable through web, browser software on devices like smartphones,, tablets, and computers., • These pages contain many types of content, including, static content like encyclopedia pages, but also, dynamic content like eBay sales, stocks, weather,, news, and traffic reports.
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Internet of things, The Internet of Things (IoT) describes the network, of physical objects—“things”—that are, embedded with sensors, software, and other, technologies for the purpose of connecting and, exchanging data with other devices and systems, over the internet.
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• Internet of things connects the devices & humans with, the learning of innovation., • Now, the IoT will be set up in a Web Development, industry to make web architecture and User Interface’s, more creative and interactive., • IoT will create advanced communication between, website layouts and operational models., • IoT has a broad intensity of things like sensors, cameras,, signaling equipment, etc., • It will ensure to solve client requests effectively and build, up the correct directions., • At present, many IoT devices may be able to display, website information and results. It includes laptops,, smart appliances like AC’s and microwave ovens, etc.,, and Industrial monitors like embedded systems., • It plays a vital role in Web Development, and it is beyond, all these technologies.
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Domain Name System, • The Domain Name System (DNS) provides a service, that maps human-readable symbolic names to, computer addresses. Browsers, mail software, and, most other Internet applications use the DNS., • The system provides an interesting example of client, server interaction because the mapping is not, performed by a single server. Instead, the naming, information is distributed among a large set of, servers located at sites across the Internet., • Whenever an application program needs to translate, a name, the application becomes a client of the, naming system.
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The client sends a request message to a name server,, which finds the corresponding address and sends a reply, message., If it cannot answer a request, a name server temporarily, becomes the client of another name server, until a server, is found that can answer the request.
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• Every host is identified by the IP address but, remembering them is very difficult and also, the IP addresses are not static., • Therefore a mapping is required to change, the domain name to IP Address. So DNS is, used to convert the domain name of the, websites to their numerical IP address., • Translation of domain name into an, equivalent IP address is called Name, resolution
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Security Aspects, • Threats (ಬೆದರಿಕೆಗಳು) and Prevention(ತಡೆಗಟ್ಟು ವಿಕೆ), • A threat is a threat which endangers a system or a practice., • In the cyber security world, a threat refers to a process, where it causes vital damage to the computer systems., The various threats are:• internet-borne attacks, eg spyware or malware, • user generated weaknesses, eg easily guessed password or, misplaced information, • inherent system or software flaws and vulnerabilities, • subvert system or software features
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Essential cyber security measures Or, Prevention Methods, • Use strong passwords, • Strong passwords are vital to good online security., Make your password difficult to guess by:, • using a combination of capital and lower-case letters,, numbers and symbols, • making it between eight and 12 characters long, • avoiding the use of personal data, • changing it regularly, • never using it for multiple accounts, • using two factor authentication, • See how to protect against password-guessing attacks.
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Control access, Make sure that individuals can only access data and services for, which they are authorized., For example, you can:, • control physical access to premises and computers network, • restrict access to unauthorised users, • limit access to data or services through application controls, • restrict what can be copied from the system and saved to storage, devices, • limit sending and receiving of certain types of email attachments, • Modern operating systems and network software will help you, to achieve most of this, but you will need to manage the, registration of users and user authentication systems – eg, passwords., • Read more about identity and access management controls.
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Put up a firewall, , • Firewalls are effectively gatekeepers between, your computer and the internet, and one of the, major barriers to prevent the spread of cyber, threats such as viruses and malware., • Make sure that you set up your firewall devices, properly, and check them regularly to ensure, they have the latest software/firmware updates, installed, or they may not be fully effective., • Read more about firewalls in server security.
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Use security software, • You should use security software, such as antispyware, anti-malware and anti-virus programs,, to help detect and remove malicious code if it, slips into your network., • Discover how to detect spam, malware and virus, attacks., • Update programs and systems regularly
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Monitor for intrusion (ಒಳನುಗ್ಗಿ ಸುವುದು), • You can use intrusion detectors to monitor system, and unusual network activity., • If a detection system suspects a potential security, breach, it can generate an alarm, such as an email, alert, based upon the type of activity it has, identified., • See more on cyber security breach detection.
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Malware:-, , • Malware is intrusive software that is designed to, damage and destroy computers and computer, systems., • Malware is a contraction for “malicious, software.”, • Examples of common malware includes viruses,, worms, Trojan viruses, spyware, adware, and, ransomware.
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Virus:, • It is one of the popular cyber security threat to the, computer systems., • It is a piece of code or program which replicates itself, and once it is hosted on the computer system it will, cause damage to the entire system., • Most of the time it is used for monetizing individuals., • Hackers inject the virus in different forms and once, the systems are affected with the virus only the, hackers will be able to allow access to the system, again., • In order to clear the virus, they demand money from, the users., • For example Ransomware , it has destructed hundreds, of individuals and companies.
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Worms:, • It is considered to be one of the harmless, threat to the computer system., • But it replicates itself and has a chance of, spreading from one computer to another, computer within the network systems., • Further, it will eat up the entire hard disk, space as it replicates itself.
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Ransomware, , • Ransomware is malicious software that gains access to, sensitive information within a system, encrypts that, information so that the user cannot access it, and then, demands a financial payout for the data to be released., • Ransomware is commonly part of a phishing scam. By, clicking a disguised link, the user downloads the, ransomware., • The attacker proceeds to encrypt specific information that, can only be opened by a mathematical key they know., • When the attacker receives payment, the data is unlocked.
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Trojan, • It is one of the most complicated threats when, compared to others., • On an analysis and observation, most of the, banking threats come from Trojan family itself., • They are able to hide from antivirus software, and their primary purpose is to steal vital, banking, information, which, ultimately, compromises your bank account and, transactions.
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Spyware, • It is kind of a Malware, once the system is affected by, this then the user activity or certain activity of the, user on the computer system can be spied., • Based on your activity, the hacker will scam you, based on your interest., • For example: if you have constantly browsed, Xbox(video Gameing) products then the hacker will, come up with a very convincing scam on Xbox and, finally cheat you.
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Adware, • This is not a harmful threat but it is one of, the annoying factors once you are affected., • Once this is installed, your computer will pop, up a lot of ads ( shows both non-adult, material and adult material).
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Keylogger:, • This is one of the powerful threat where most, of the information is tracked., • So based on your keystrokes, keylogger will, be able to keep a track of your activity., • With the help of this program, the hacker will, be able to find out your personal information, like username and password.
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Modes of Malware Distribution, • Email attachments, Viruses and Trojans are often disguised as innocent email, attachments in phishing emails. Users are tricked into, downloading malware that poses as an invoice, form,, image, or other document. Once on the user’s device,, the malware either unpacks itself or waits for the, user to attempt to open it before executing its code.
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Links in phishing email scams or malicious, Web sites, Often, phishing email scams try to direct victims to, Web sites under the pretense of a threat (“your, account will be disabled”), warning (“suspicious, activity has been detected on this account”), or deal, (“limited-time offer if you click now”). These links, typically lead to malicious sites that download, malware to the victim’s device when they load the, page.
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Malvertising, Malvertising, or malicious advertising, downloads, malware to a victim’s device when the victim, loads a Web page that displays the malicious, advertisement. Malvertising is a pervasive, problem because it is poorly controlled and can, appear even on legitimate Web sites.
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• Infected storage devices, • Some social engineers leave malware-infected thumb, drives or other storage devices in public locations where, they’re likely to be discovered., • When someone plugs the storage device into a computer, to determine its contents, malware in the device can, transfer itself to the computer and infect it., • Never plug suspicious or unknown storage devices into a, computer., • Negligence, All of these attack methods are made easier if a computer’s or, device’s owner has not kept the software on the computer, or device up to date., In fact, this is often how worms spread–taking advantage of, system vulnerabilities before they can be patched.
