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INTRODUCTION =>Linking of two or more computing devices to share resources is networking. =>Virtual Private Network is a type of private network that uses public telecommunication, such as the Internet, instead of leased lines to communicate .
=> VPN provides a secure channel between local computer and a computer at the remote location. => Private networks rely on leased lines to transfer data which is more costly but Virtual Private Network is like a Wide area Network that relies on the internet to transfer data.
VPN Topology : Type of VPNs =>Remote Access VPN =>Site-to-Site VPN 1)Intranet VPN 2)Extranet VPN
Remote Access VPN =>Remote-access, called as virtual private dial-up network (VPDN) =>LAN connection used by a company that has employees who need to connect to the private network from various remote locations. =>Remote-access VPNs permit secure encrypted connections between a company's private network.
Site-to-Site VPN =>Intranet-based - 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. =>Extranet-based - 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.
VPN components • Protocols • Security
VPN : Protocols PPTP- Point-to-Point Tunneling Protocol => PPTP is one of VPN's first protocols built on PPP to provide remote access for VPN solutions. =>PPTP uses authentication mechanisms within PPP. L2F- Layer Two Forwarding Protocol =>L2F accepts other authentication mechanisms and allows tunnels to support more than one connection.
VPN : Protocols L2TP - Layer Two Tunneling Protocol =>The best features of PPTP and L2F were combined to form L2TP. =>It exists in the second layer (data link) of the OSI(Open Systems Interconnect) model and so its name L2TP.
VPN : Protocols Internet Protocol Security (IPSec) =>IPSec is a complete VPN protocol solution. =>IPSec uses a number of encryption technologies to provide confidentiality and data integrity. =>IPSec's strong security measures are designed mainly for IP packets and cannot handle multi- protocol.
VPN : Security • Encryption • Technique for scrambling and unscrambling information • Unscramble – called clear-text • Scrambled information – cipher-text • Keys • Secret code that the encryption algorithm uses to create a unique version of cipher-text • 8-bits keys = 256 combinations or two to the eighth power • 16-bits keys = 65,536 combinations or two to the 16th power
Authentication • Determine if the sender is the authorized person and if the data has been redirect or corrupted • User/System Authentication • Data Authentication
VPN : software • Client-Servers • VPN Server
=>Client-Server Network architecture is where the PC is the requesting machine and the server the supplying machine.=>VPN server software is not needed as VPN software for Windows based workstations or Servers have VPN capability incorporated in the operating systems.
=> Security should be the main factor as worms and other cyber attacks on server based systems are numerous. =>If large amount of clients then a dedicated single system for VPN services is better or other services on the corporate network will slow down.
VPN : Gateway => A network gateway in that sense refers to the conversion of one network protocol to another. =>Gateway serves as an entry and exit point where some sort of processing is done on the information that passes through it. =>A network gateway is a system that joins two networks together. =>It can be implemented completely in software, completely in hardware or as a combination of the two.
VPN : Router • Router is usually a device/computer with at least two network interface cards support the Internet protocol. • A router receives packets from an interface card and reads the address on the IP packet and forwards it to an appropriate output network interface. • A VPN router specifies network IP addresses that are known with appropriate network interface to be used for a packet to reach the destination.
VPN : Tunnel • VPN tunnel is used to send the data. • Multiple protocols are pushed into given network or given any topology. • PPTP-Point to point tunneling protocol/L2TP-Layer 2 Tunneling protocol encapsulates private network traffic in packets to be transmitted over public networks (TCP/IP).
VPN : Advantages • Cost Savings . • Extend geographic connectivity. • Improve security • Provide broadband networking compatibility • Improve productivity • Reliable
VPN : Disadvantages • VPNs require an in-depth understanding of public network security • VPN require more tools.