What Is Virtual Private Network Computer Science Essay

Virtual Private Network is a web which requires usage of public engineering like the cyberspace in order to enable assorted organisations and users a unafraid entree to their personal webs. It provides the same security options that a wired web provides by utilizing a “ tunneling ” mechanism and coding informations so that it is secured.

In general footings, VPN is a connexion established between multiple networking devices by sharing substructure and supplying a safer and more unafraid platform for users ‘ to derive entree to their personal webs.

Figure: Virtual Private Network

the undermentioned characteristics must be must taken into history while making a VPN:

It must supply security at the highest degree

the web must be Reliable

Scalability is an of import characteristic as good

A good managed web

Management of policy


1 ) Encapsulation

Encapsulation is the procedure of adding excess information to the original informations, like a heading and routing information. This engineering besides follows encapsulation procedure which allows informations and information to go through through a public web.

2 ) Authentication

Authentication are of three different types:

I ) User degree hallmark

A VPN client that is trying a user-level hallmark method by linking with the VPN waiter via a ( PPP ) is authenticated by the VPN waiter and it besides checks whether the VPN client is decently authorized or non.

For supplying protection against bogus VPN waiters, the client can authenticate the waiter in the presence of a common hallmark.

two ) Computer-level hallmark utilizing the Internet Key Exchange

The hallmark of VPN client and waiter is done by each other at the computing machine degree by agencies of the Internet Key Exchange ( IKE ) protocol to trade computing machine certifications or a pre-shared key.

three ) Data originality and unity hallmark

Data is encrypted with a cryptanalytic checksum which is known to the transmitter and the receiving system of the informations in order to corroborate that the information sent on through the connexion was non modified in theodolite and was created by the transmitter himself at his terminal of the connexion.

3 ) Encoding of informations

To better protect and procure the information during its transmittal over the public web, the information is encrypted by the transmitter and is decrypted when received by the receiving system. This procedure depends upon the transmitter and the receiving system of the informations who are utilizing a common encoding key while conveying it.

Encrypted informations sent along the VPN connexion are nonmeaningful to people who do non hold the encoding key. The encoding key ‘s length is an of import security consideration and users can use a assortment of computational techniques to find the encoding key. It is indispensable to use the biggest cardinal size possible to do certain informations is protected.

4 ) Address Allocation

A practical interface that represents all connexions made is created during the constellation of a VPN. An interface is created on the client when a connexion is established. The practical interfaces of the client and the sever must be assigned IP reference and these IPs are assigned by the waiter. The server gets IP for it and clients use the Dynamic Host Configuration Protocol ( DHCP ) to acquire IP references. The practical interface of the client and the waiter is connected utilizing a Point to Point VPN connexion.

During the establishment procedure of the VPN connexion, the assignment of DNS ( Domain Name System ) and WINS ( Windows Internet Name Service ) occurs and the client gets IP of the DNS and WINS from the waiter.

Network Address Translation

NAT facilitates users to conceal unregistered IP ‘s among many registered IP ‘s which so helps in protecting the internal web. Since many private references can be represented by a little set of registered references, NAT helps work out the IP reference depletion job. besides helps to relieve the IP reference depletion job.



A few companies have been able to unite characteristics of SSL and IPSec and other legion sorts of VPN connexions. Hybrid VPN waiters accept connexions from multiple sorts of VPN clients. It is expensive but it offers higher flexibleness at both clients and waiter degrees

Under Hybrid Internet VPN, the web devices are connected via cyberspace. It is used in state of affairss where ISPs of two or more webs are different. VPN Client users are able to entree waiters from assorted topographic points as per there demands.

It reduces cost burden of long distance related with dial-up connexion and ensures a secure web entree to the users where the may physically be.

Figure: Hybrid INTERNET VPN

2 ) Intranet VPN

Intranet VPN consists of multiple networking devices being connected within the same web and negotiating to a secure communicating medium via the Internet which is known as a tunnel.

An illustration of Intranet VPN is an bing web in different edifices that are connected to a mainframe which has secured entree via private lines which enables clients from webs on both sides of the tunnel to pass on with each other like pass oning in the same web. This requires strong encoding of informations.

It significantly lowers the cost over the old fashioned leased-line engineering by the usage of Internet to associate long distance webs.





Hybrid cyberspace VPN connexion is the combination of the characteristics of SSL, IPSec and assorted other types of VPN webs.

Intranet VPN connexion is the practical web created between same types of webs via the medium of cyberspace or local connexion.

It is adept to accept connexions from legion types of VPN clients.

It can accept connexions from merely its sort of VPN clients.

It provides higher flexibleness at both client and waiter degree

It relatively provides less flexibleness than a intercrossed cyberspace VPN connexion.

It is expensive to set up and run

It is relatively cheaper to set up and run than intercrossed cyberspace.


1 ) Mandate

Users that have been authorized are merely accepted to keep a VPN connexion.

VPN connexions do non necessitate the creative activity of extra user histories. The waiter merely uses histories specified in the available user histories database.

How security works at connexion

* A PPTP tunnel is created with the VPN waiter.

* A challenge is sent by the waiter.

* An encrypted answer is sent to the waiter.

* The answer is checked against the user database.

* The connexion is authorized when the history is valid.

2 ) Authentication

A critical security concern is the VPN hallmark of clients by the waiter. Authentication procedure has two degrees:

I ) Computer-level hallmark

Computer-level hallmark is conducted by the interchanging computing machine certifications or a preshared key while esablishing the IPSec association..

two ) User-level hallmark

The distant entree client is authenticated who requests the VPN connexion before informations is sent over public web.

3 ) Data encoding

There is a high hazard of malicious intercession during directing of informations between client and the waiter over a shared cyberspace web. In order to keep informations confidentiality the informations must be encrypted.

Data encoding is the procedure of transforming or change overing the field text into zero text by using mathematical computations and algorithms. The zero texts are such which are non-readable to other people. The waiter can be configured to use informations encoding where users linking to that peculiar waiter must code the information they send or they wont be allowed a connexion.

Data encoding are of two types and they are: symmetric and asymmetric. Symmetrical system brings in usage a common key which is shared and known by both the transmitter and receiving system of the informations while asymmetric system uses two keys, public and private key. The populace is used to code informations to direct to the proprietor and to decode that information, the private key is required.

4 ) Package filtrating

While configuring a distant entree waiter with a distant entree apparatus ace, the naming router is configured every bit good.

The computing machine forwards IP packages between the Internet and intranet because IP routing is enabled on intranet interfaces which provides a direct and routed connexion. The intranet can be protected so that merely the traffic sent and received over secured connexions are forwarded to the intranet.

In the being of a firewall, the package filters on the firewall must be configured in order to go through traffic between the VPN router and the routers available on the cyberspace.


With the constitution of a Virtual Private Network, the client computing machine is connected with waiter and different computing machines as if they are connected in the same web via the agencies of cyberspace. Assorted networking maps like Mapping of web thrusts, leting distant entree, etc. , can be performed as if the computing machines are in the same web. VPN besides provides the same degree of security that a wired medium provides in order to keep a high information confidentiality, therefore, doing the users ‘ able to entree their web anytime from anyplace they prefer without any outside menace or any other proficient troubles.