Virtual means not real or in a different state of being. In a VPN, private communication between two or more devices is achieved through a public network. Therefore, the communication is virtually but not physically there.
Private means to keep something a secret from the general public. Although those two devices are communicating with each other in a public environment, there is no third party who can interrupt this communication or receive any data that is exchanged between them.
A Network consists of two or more devices that can freely and electronically communicate with each other via cables and wire. A VPN is a network. It can transmit information over long distances effectively and efficiently.

• A VPN is a combination of software and hardware that allows mobile employees, telecommuters, business partners, and remote sites to use a public or “unsecured” medium such as the Internet to establish a secure, private connection with a host network.
• It uses "virtual" connections routed through the internet from the business's private network to the remote site.
• VPN extends a private network and the resources contained in the network across public networks like the Internet.

• Remote-Access VPN
• Site-to-Site VPN (Intranet-based and Extranet-based)

• A remote access VPN is for home or travelling users who need to access their central LAN from a remote location. They dial their ISP and connect over the internet to the LAN.
• This is made possible by installing a client software program on the remote user’s laptop or PC that deals with the encryption and decryption of the VPN traffic between itself and the VPN gateway on the central LAN.
• Firewall act as a breaking point. It doesn’t allow any request from outside and also doesn’t sent request from inside.

• If a company has one or more remote locations that they wish to join in a single private network, they can create an intranet VPN to connect LAN to LAN.

• When a company has a close relationship with another company (for example, a partner, supplier or customer), they can build an extranet VPN that connects LAN to LAN, and that allows all of the various companies to work in a shared environment.

• A technique used to gain unauthorized access to computers, whereby the intruder sends messages to a computer with an IP address indicating that the message is coming from a trusted host.

• Original IP Address can be hidden.
• VPN spoofed IP Address only shown when unauthorised access. So, it is fully secured. This type of IP Spoofing is used in Banks & other places also.

• VPN protocols represent the processes and sets of instructions. VPN providers rely on in order to ensure VPN users get to enjoy stable, secure VPN client-VPN server communications. At its core, a VPN protocol is basically a mix of transmission protocols and encryption standards.

• PPTP - Point-to-Point Tunnelling Protocol
• L2TP - Layer 2 Tunnelling Protocol
• IPsec - Internet Protocol Security
• SOCKS - It is not used as much as the ones above

• Encryption is a method of "scrambling" data before transmitting it onto the internet.
• Digital Signature - For Authentication

• Data encapsulation, also known as data hiding, is the mechanism whereby the implementation details of a class are kept hidden from the user. The user can only perform a restricted set of operations on the hidden members of the class by executing special functions commonly called methods.

• Go to whatismyipaddress.com website in browser.
• There are also other ways to get IP address.
• Commands used:
• ipconfig (Computer)
• ifconfig (Termux)

• Go to Mobile Settings and search for VPN
• Add VPN by fill out the details of name, choose the type of protocals, server address, user name and password. And enable to connect VPN.

• Go Again to whatismyipaddress.com website.

• The original IP address will be hidden. And the spoofed IP Address will be visible.