What is VPN - BZU PAGES: Find Presentations, Reports, Student's Assignments and Daily Discussion; Bahauddin Zakariya University Multan

What is VPN · 18-09-2009, 04:33 PM

The Virtual Private Network - VPN - has attracted the attention of many organizations looking to both expand their networking capabilities and reduce their costs.

The VPN can be found in workplaces and homes, where they allow employees to safely log into company networks. Telecommuters and those who travel often find a VPN a more convenient way to stay connected to the corporate internet. No matter your current involvement with VPNs, this is a good technology to know something about. This VPN tutorial involves many interesting aspects of network protocol design, Internet security, network service outsourcing, and technology standards.

What Exactly Is A VPN?

A VPN supplies network connectivity over a possibly long physical distance. In this respect, a VPN is a form of WAN The key feature of a VPN, however, is its ability to use public networks like the Internet rather than rely on private leased lines. VPN technologies implement restricted-access networks that utilize the same cabling and routers as a public network, and they do so without sacrificing features or basic security.

VPN supports at least three different modes of use:

Remote access client connections
LAN-to-LAN internetworking
Controlled access within an intranet

VPN Pros and Cons

Like many commercialized network technologies, a significant amount of sales and marketing hype surrounds VPN. In reality, VPNs provide just a few specific potential advantages over more traditional forms of wide-area networking. These advantages can be significant, but they do not come for free.

The potential problems with the VPN outnumber the advantages and are generally more difficult to understand. The disadvantages do not necessarily outweigh the advantages, however. From security and performance concerns, to coping with a wide range of sometimes incompatible vendor products, the decision of whether or not to use a VPN cannot be made without significant planning and preparation.

Technology Behind VPNs

Several network protocols have become popular as a result of VPN developments:

PPTP
L2TP
IPsec
SOCKS

These protocols emphasize authentication and encryption in VPNs. Authentication allows VPN clients and servers to correctly establish the identity of people on the network. Encryption allows potentially sensitive data to be hidden from the general public.

Many vendors have developed VPN hardware and/or software products. Unfortunately, immature VPN standards mean that some of these products remain incompatible with each other.

VPN Solutions and Key Features

A VPN supplies network connectivity over a possibly long physical distance. In this respect, a VPN is a form of WAN VPNs enable file sharing, video conferencing and similar network services. Virtual private networks generally don't provide any new functionality that isn't already offered through alternative mechanisms, but a VPN implements those services more efficiently / cheaply in most cases.

A key feature of a VPN is its ability to work over both private networks as well as public networks like the Internet. Using a method called tunneling, a VPN use the same hardware infrastructure as existing Internet or internet links. VPN technologies includes various security mechanisms to protect the virtual, private connections.
Specifically, a VPN supports at least three different modes of use:

Internet remote access client connections
LAN-to-LAN internetworking
Controlled access within an intranet

Internet VPNs for Remote Access

In recent years, many organizations have increased the mobility of their workers by allowing more employees to telecommute. Employees also continue to travel and face a growing need to stay connected to their company networks.

A VPN can be set up to support remote, protected access to the corporate home offices over the Internet. An Internet VPN solution uses a client/server design works as follows:

1. A remote host (client) wanting to log into the company network firstconnects to any public ISP.

2. Next, the host initiates a VPN connection to the company VPN server. This connection is made via a VPN client installed on the remote host.

3. Once the connection has been established, the remote client can communicate with the internal company systems over the Internet just as if it were a local host. Before VPNs, remote workers accessed company networks over private leased lines or through dialup remote access servers. While VPN clients and servers careful require installation of hardware and software, an Internet VPN is a superior solution in many situations. VPNs for Internetworking

Besides using virtual private networks for remote access, a VPN can also bridge two networks together. In this mode of operation, an entire remote network (rather than just a single remote client) can join to a different company network to form an extended intranet. This solution uses a VPN server to VPN server connection. Intranet / Local Network VPNs

Internal networks may also utilize VPN technology to implement controlled access to individual subnets within a private network. In this mode of operation, VPN clients connect to a VPN server that acts as the network gateway.

This type of VPN use does not involve an Internet Service Provider (ISP) or public network cabling. However, it allows the security benefits of VPN to be deployed inside an organization. This approach has become especially popular as a way for businesses to protect their WIFI local networks.