• Comodo Antivirus is the only antivirus solution that provides protection against all new viruses.It optimizes system performance.
• Comodo Antivirus allows only safe applications to run.

• Comodo antivirus provides on-access protection from viruses and other malware.
• Virus definitions are regularly updated, in the background.
• Works with Windows (10, 8, 7, Vista, XP).
• Includes a “Game Mode” (silent detection).
• 64-bit versions are also available.

• Several other programs and system settings are included that you may want to disable.
• There is no use of business only we can use at home.
• Very large setup file (170 MB) that may take a while to download.
• Initial updates may take a while to complete.

• Proactive antivirus engine that automatically detects and eliminates viruses, worms, and other malware.
• Powerful on-demand.
• Powerful on-access.
• Perfect scheduling scan capabilities.
• Easily drag and drop items onto the home screen to run an instant virus scan.

A port has the following characteristics −

• External devices are connected to a computer using cables and ports.
• Ports are slots on the motherboard into which a cable of external device is plugged in.
• Examples of external devices attached via ports are the mouse, keyboard, monitor, microphone, speakers, etc.

• A port number is the logical address of each application or process that uses a network or the Internet to communicate.
• A port number uniquely identifies a network-based application on a computer.
• Each application/program is allocated a 16-bit integer port number.
• This number is assigned automatically by the OS, manually by the user or is set as a default for some popular applications.

• Protocol is a special set of rules for communication data.
• Network protocol = Rules and conventions/conditions for communication between network devices.
• Network protocols defines the mechanism of devices to identify and establish the connections between each other + formatting rules that specify how data is packaged into messages sent and received.

• A Media Access Control (MAC) address is a 48-bit address stored in the network Interface card.
• It is used for communication between two hosts in an Ethernet environment.
• It is nothing but a hardware /physical address of a computer.
• A MAC address is supposed to be globally unique and this will not be duplicated.
• The 48 bit contains – First 24 bits ( User ID -> Card Buyer ID ) + second 24 bits (card manufacturer)
• The address is written in the form of 12 hexadecimal digits. For example, consider the following MAC address:
  • D8-D3-85-EB-12-E3

• Every hexadecimal character represents 4 bits, so the first six hexadecimal characters represent the vendor (in this case, Hewlett Packard).

• Four levels of addresses are used in an internet employing the TCP/IP protocols:
  • Physical Addresses
  • Logical Addresses
  • Port Addresses
  • Specific Addresses

• Click the Network Icon on Taskbar
• Click the connected network and click the properties which are shown in the figure

• The network setting window open and shows the mac address.

• Open command prompt and type getmac to get the mac address

• Navigate to Control Panel > Network and Internet > Network Connections
• Right click the connection and click status within the dropdown

• Click Details buttons in the status window
• Then the Network Details windows open and shows the MAC address(Physical address)

• Open command prompt and type ipconfig /all (have a gap between g and /).

• Spoofing is that the act of disguising a communication from an unknown resource as being from a well-known, trusted resource.
• Spoofing will apply to emails, phone calls, and websites, or will be a lot of technical, like a pc spoofing an IP address, Address Resolution Protocol (ARP), or Domain name System (DNS) server.
• Spoofing will be used to gain access to a target’s personal information, describe malware through infected links or attachments, bypass network access controls, or distribute traffic to conduct a denial-of-service attack.
• Spoofing is usually the means a vulgar actor gains access so as to execute a bigger cyber attack like a complicated persistent threat or a man-in-the-middle attack.
• Successful attacks on organizations will cause infected pc systems and networks, data breaches, and/or loss of revenue-all vulnerable to have an effect on the organization’s public reputation.
• Additionally, spoofing that ends up in the rerouting of web traffic will overwhelm networks or lead customers/clients to malicious sites aimed at stealing info or distributing malware.

• Email spoofing is that the fake of an email header so the message seems to have originated from somebody or somewhere apart from the particular source.
• Email spoofing may be a plan of action utilized in phishing and spam campaigns because people are more likely to open an email after they assume it’s been sent by a legitimate source.
• The goal of email spoofing is to need recipients to open, and probably even answer, a solicitation.

• IP (Internet Protocol) forms the third layer of the ISO model. It is the network protocol which is used for the transmission of messages over the internet. Every email message sent has details in the message header of the IP address of the sender (source address). Hackers and scammers alter the header details to mask their true identity by editing the source address. The emails then look to have been transmitted by a trusted source. There are two types of IP spoofing.
  • Man in the Middle Attacks
  • Denial of Service (DoS) Attacks

• Caller ID spoofing is when a caller with intent fakes the information transmitted to your caller ID display to disguise their identity.
• Spoofing is often used as part of an attempt to trick someone into giving away valuable personal information so it can be used in fraudulent activity or sold illegally, but also can be used legitimately, for example, to display the toll-free number for a business.

• ARP poison routing (APR) or ARP cache poisoning, a method of attacking an Ethernet LAN by updating the target computer’s.
• ARP cache with both a fake ARP request and reply packets in an effort to change the Layer 2 Ethernet MAC address (i.e., the address of the network card) to one that the attacker can monitor.
• Because the ARP replies have been fake, the target computer sends frames that were meant for the original destination to the attacker’s computer first so the frames can be read.
• A successful APR attempt is invisible to the user.

• DNS (Domain Name System) servers resolve URLs and email addresses to corresponding IP addresses.
• DNS spoofing allows attackers to distract traffic to a different IP address, leading victims to sites that extent malware.

• Website spoofing means when a website is designed to copycat an existing site known and/or trusted by the user.
• Attackers use these sites to gain login and other personal information from users.

• IP stands for Internet Protocol which is the communications protocol of digital message formats and rules for exchanging messages between computers across a single network or a series of interconnected networks, using the Internet Protocol Suite (often referred to as TCP/IP
• Internet Protocol is connectionless and unreliable protocol. It ensures no guarantee of successfully transmission of data.
• Messages are exchanged as datagrams, also known as data packets or just packets.
• IP consisting of four abstraction layers : link layer (lowest), Internet layer, transport layer and application layer (highest).

• The Domain Name System (DNS) is the phonebook of the Internet. Humans access information online through domain names, like wikitechy.com. Web browsers interact through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources.
• Each device connected to the Internet has a unique IP address which other machines use to find the device. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as 2400:cb00:2048:1::c629:d7a2 (in IPv6).
• The DNS uses TCP Port 53 for zone transfers, for maintaining coherence between the DNS database and the server.

• DND means Do Not Disturb.This is an initiative by TRAI (Telecom Regulatory Authority of India) to save consumers from unsolicited calls/SMS.
• Register with the service provider’s Do No Disturb registry to avoid receiving unwanted telemarketing calls and messages.
• In turn the service provider register your number at the National Do Not Call (NDNC) registry within 45 days.
• Telemarketers have to verify the calling number list in the NDNC registry before making a call.
• So rest assured, the telemarketers will not trouble you else they will be fined for calling you.

• It allows phone users to disable audible ringing for incoming calls.
• When DND is enabled, incoming calls do not ring on the phone, however there is visual alerting and the call information displays, and a call can be answered if desired.
• When a phone calls in the DND state, the message “Ring out DND” displays on the calling phone that indicate the target phone is in the DND state.

• DHCP (Dynamic Host Configuration Protocol) is a protocol used to provide quick, automatic, and central management for the distribution of IP addresses within a network.
• DHCP is also used to configure the proper subnet mask, default gateway, and DNS server information on the device.
• DHCP allows hosts to obtain required TCP/IP configuration information from a DHCP server.

• A DHCP server is used to concern single IP address and automatically configure other network information.
• Maximum the home and small businesses, the router acts as the DHCP server. In large networks, a single computer might act as the DHCP server.
• A device (the client) requests an IP address from a router (the host), after which the host assigns an available IP address to allow the client to communicate on the network.
• Once a device is turned on and connected to a network that has a DHCP server, it will send a request to the server, called a DHCPDISCOVER request.
• After the DISCOVER packet reaches the DHCP server, the server goes to hold on to an IP address that the device can use, and then offers the client the address with a DHCPOFFER packet.
• Once the offer has been made for the chosen IP address, the device responds to the DHCP server with a DHCPREQUEST packet to accept it, after which the server sends an ACK that’s used to confirm that the device has that specific IP address and to define the amount of time that the device can use the address before getting a new one.
• If the server decides that the device cannot have the IP address, it will send a ACK.

• Ensuring cybersecurity requires the coordination of efforts throughout an information system, which includes:
  • Network security
  • Application security
  • Endpoint security
  • Data security
  • Identity management
  • Database and infrastructure security
  • Cloud security
  • Mobile security
  • Disaster recovery/business continuity planning
  • End-user education
• The most difficult challenge in cyber security is the ever-evolving nature of security risks themselves.
• The traditional approach has been to focus resources on crucial system components and protect against the biggest known threats, which meant leaving components undefended and not protecting systems against less dangerous risks.
• Today, this approach is insufficient, as the threats advance and change more quickly than organizations can keep up with. As a result, advisory organizations promote more proactive and adaptive approaches to cyber security.

• Ransomware is a type of malware that involves an attacker locking the victim’s computer system files — typically through encryption — and demanding a payment to decrypt and unlock them.
• Malware is any file or program used to harm a computer user, such as worms, computer viruses, Trojan horses and spyware.
• Social engineering is an attack that relies on human interaction to trick users into breaking security procedures in order to gain sensitive information that is typically protected.
• Phishing is a form of fraud where fraudulent emails are sent that resemble emails from reputable sources; however, the intention of these emails is to steal sensitive data, such as credit card or login information.

• A whitelist is a list of e-mail addresses or domain names from which an e-mail blocking program will allow messages to be received.
• The list can be gradually compiled over a period of time, and can be edited whenever the user wants.
• When a whitelist is used, all entities are denied access, except those included in the whitelist.

• A network administrator may be configure a firewall with a whitelist that allows only specific IP addresses to access the network.
• A protected directory within a website uses whitelist for the purpose of provide limit access to certain IP addresses.
• Some e-mail system users use whitelist for receiving only accept messages from the e-mail addresses.
• Programmers can use whitelists within a program to ensure only certain objects are modified.

• Hardware firewalls are systems that are independent of the computers they protect that filter the Internet as information passes into a computer.
• Most broadband Internet routers have their own firewall built in.
• In general, hardware firewalls work by examining the data that flows in from the Internet and verifying whether that information is safe.
• The ZyXEL ZyWALL, which is a Unified Security Gateway with a firewall and other security features.
• Cost: $100 to ~$500
• NAT, DCHP, Email Notification.
• Easier for computers to locally share folders/Printers.
• Additional function available & can protect other devices.

• Software firewalls are designed to protect a computer by blocking certain programs from sending and receiving information from a local network or the Internet.
• The Windows Firewall, an example of a firewall software program included with Microsoft Windows.
• Cost: Free to $30 per computer.
• Each machine need to be configured.
• Firewall may be interfere with local network sharing.

• This layer conveys the bit stream across the network either electrically, mechanically or through radio waves.
• The physical layer covers a variety of devices and mediums, among them cabling, connectors, receivers, transceivers and repeaters.

• This layer sets up links across the physical network, putting packets into network frames.
• This layer has two sub-layers: the logical link control layer and the media access control layer (MAC). MAC layer types include Ethernet and 802.11 wireless specifications.

• This layer handles addressing and routing the data — sending it in the right direction to the right destination on outgoing transmissions and receiving incoming transmissions at the packet level. IP is the network layer for the internet.

• This layer manages packetization of data, then the delivery of the packets, including checking for errors in the data once it arrives.
• On the internet, TCP and UDP provide these services for most applications as well.

• This layer sets up, coordinates and terminates conversations. Its services include authentication and reconnection after an interruption. On the internet, Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) provide these services for most applications.

• This layer is usually part of an operating system (OS) and converts incoming and outgoing data from one presentation form to another.

• This is the layer at which communication partners are identified ,network capacity is assessed and where the data or application is presented in a visual form.
• This layer is not the application itself, it is the set of services an application should be able to make use of directly, although some applications may perform application-layer functions.

1. 1. The email is sent from a public email address – The sender’s email address, as this can help identify if the person is truly who they claim to be. Frequently, the criminal will use a public email address such as gmail.com. If your bank or team mate is going to email you, it will come from a company email account with the company name in the email address.
   2. Strange attachments – If you receive an unexpected email or an email from someone you don’t know asking you to open an attachment, do not open it. These attachments can contain malware that can damage your computer and capture your personal data.
   3. The creation of a sense of urgency – Phishing emails often ask recipients to verify personal information, such as bank details or a password. They can create a sense of urgency by warning that your account has experienced doubtful activity or imagining to be someone you know who is in urgent need of financial help.These are massive warning signs. If you are ever unsure, contact the company or person using the contact details you already have for them or that are on their genuine website. Never use any contact details or click any links provided in the email.How to detect phishing ? – The email is sent from a public email address.Look at the sender’s email address, as this can help identify if the person is truly who they claim to be. Often, the criminal will use a public email address such as gmail.com.

1. Links to unrecognised sites or URLs that misspell a familiar domain name – Phishing emails may ask you to click a link within the email. By hovering your mouse over the link or address, you can see the linked site’s true URL. These URLs can be slightly misspelled or completely different to what you are expecting, so always double check before you click.
2. Poor spelling and grammar – You can often detect a phishing email by the way it is written. The writing style might be different to that usually used by the sender and it might contain spelling mistakes and poor grammar.

• Spam is garbage mail or garbage newsgroup postings and also the spam is defined as unsolicited email.
• However, if a long-lost person finds your email address and sends you a message, this could hardly be called spam, even though it is unsolicited.
• Real spam is generally email advertising for some product sent to a mailing list or newsgroup.
• Unsolicited commercial email messages sent in bulk, often to a purchased (or stolen) mailing list that contained your address.
• Counterfeit messages from reliable senders that attempt to trick you into supplying your personal information.
• Misleading messages from people you know whose email accounts have been hacked.
• Not all spam is illegal, but some of it is.

• An Internet service provider (ISP) is a company that provides Internet access to organizations and home users.
• ISP provides with Internet access, usually for a payment. Without an ISP, you wouldn’t be able to shop online, access Facebook, or read this page.
• Connecting to the Internet requires specific telecommunications, networking, and routing equipment.
• ISPs allow users access to networks that contain the required equipment, enabling users to establish Internet connectivity.
• ISPs are responsible for ensure that you can access the Internet, routing Internet traffic, resolving domain names, and maintaining the network infrastructure that makes Internet access possible.
• While the core function of an ISP is to provide Internet access, many ISPs do much more. ISPs also offer services like web hosting, domain name registration, and email services.
• An Internet service provider is also known as an Internet access provider (IAP).

• The internet service providers (ISPs) are very competitive market with lots of different offerings and deals. Even household names, such as banks and retailers, provide ISP services.
• Internet service providers connect your personal or business computer, laptop, mobile device etc to the internet. ISPs may be commercial, non-profit, privately owned or community owned companies.
• Most providers offer the same types of internet services to customers, including:
  • Internet Access
  • Email Access
  • Domain Name Registration
  • Web hosting
  • Co-Location (or data centre services)

• Some ISPs also provide services such as website design or development of e-commerce facilities. See different types of ISPs.

• ISPs use a range of technologies to enable customers’ connection to their network. The most common types of internet connections include:
  • Dial-up or analogue
  • DSL (digital subscriber line)
  • Cable broadband
  • Fibre optic broadband
  • Wireless or Wi-Fi broadband
  • Satellite and mobile broadband
  • Dedicated leased line

• Most ISPs offer a range of packages aimed at different levels of users, based on factors such as the speed of connection, the number of email addresses needed or the amount of free web space.

• Traverse the given list.
• Insert each encountered node into a hash table.
• If the current already present ,that means the cycle is present or not.

• Binary tree is a special type of data structure. In binary tree, every node can have a maximum of 2 children, which are known as Left child and Right Child.
• It is a method of placing and locating the records in a database, especially when all the data is known to be in random access memory (RAM).
• A binary tree has the benefits of both an ordered array and a linked list as search is as quick as in a sorted array and insertion or deletion operation are as fast as in linked list.