Hi! Thanks for the question.
I will answer your questions in a point-by-point manner. I highly
recommend that you read the articles in their entirety to get a better
grasp of the concept.
1. What is virtual private network?
?A VPN supplies network connectivity over a possibly long physical
distance. In this respect, a VPN is a form of Wide Area Network
(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 Tutorial - Introduction to VPN?
http://compnetworking.about.com/library/weekly/aa010701a.htm
?The Virtual Private Network (VPN) has risen fast to become a major
networking technology in just a few years. With a VPN, you can send
data, via a shared or public network in a manner that emulates a
point-to-point private link, between two networks (routers), between
two servers, or between a client and a server. We will focus only the
VPN connection mode between a client and a server. In this mode, the
remote PC (installed with VPN client software) utilizes existing
telecommunications infrastructures (e.g., phone lines, broadband
services, dedicated Internet link, etc) and a tunneling protocol
(incorporated with other authentication and encryption protocols) to
securely access resource inside your Telecoms Network through a VPN
server sitting at your Perimeter Gateway.?
?What is VPN?
http://www.cdc.uk.net/firewall/what_is_vpn.htm
?A Virtual Private Network (VPN) is a network that uses the Internet
or other network service as its Wide Area Network (WAN) backbone. In a
VPN, dial-up connections to remote users and leased line or Frame
Relay connections to remote sites are replaced by local connections to
an Internet service provider (ISP) or other service provider's point
of presence (POP). A VPN allows a private intranet to be securely
extended across the Internet or other network service, facilitating
secure e-commerce and extranet connections with business partners,
suppliers and customers.There are three main types of VPN:?
?Virtual Private Networks A Technology Overview?
http://www.enterasys.com/products/whitepapers/vpn/9011742.html
Additional Resources about the basics of VPN:
?Introduction to VPN (Virtual Private Networks)?
http://download.smoothwall.net/pdf/20020730.vpnintro.pdf
?VPN - Virtual private Networking, an overview?
http://www.homenethelp.com/vpn/
?Virtual Private Networks An overview?
http://www.intranetjournal.com/foundation/vpn-1.shtml
?Introduction to VPN - Technology Overview?
http://compnetworking.about.com/library/weekly/aa010701d.htm
----------------------------
2. How is it used? How does it work?
Uses of VPN:
?The emerging application areas are remote access, site-to-site
connectivity, extranets and an all-encompassing "other" category.?
A.) ?When it comes to remote-access VPNs, the basic concept is to give
telecommuters and mobile workers a way to get back to a corporate
network over the Internet or a service provider's backbone.?
B.) ?The next general application of VPNs is for site-to-site
connectivity. As in the remote-access scenario, branch offices are
connected to corporate headquarters through tunnels that transport
traffic over the Internet or via a provider's backbone.?
C.) ?The third emerging application for VPNs is extranets. There are a
number of ways to create extranets that do not involve VPN technology,
but, VPN-based extranets give IT managers another option.?
?The basic idea of VPN-based extranets is to use the access control
and authentication services with a VPN implementation to deny or grant
customers, trading partners and business associates access to specific
information that they may need to conduct business.?
?Does Everybody Really Know What A VPN Is??
http://www.internetwk.com/VPN/paper-2.htm
?What is a VPN and what can it do??
http://compnetworking.about.com/library/weekly/aa010701b.htm
How does a VPN Work?
Our next articles will show in detail how a typical VPN works.
?How Virtual Private Networks Work?
http://computer.howstuffworks.com/vpn.htm/printable
?How VPN Works?
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windowsserver2003/proddocs/techref/w2k3tr_vpn_how.asp
-----------------------------
3.) Does it have any advantages or disadvantages?
Yes! Just like any other type of technology, VPNs have their own
advantages and disadvantages.
Advantages:
?Cost savings in many ways: Using VPN to connect networks eliminates
the need for long, expensive leased-lines such as T1, T3, OC3, etc
lines. Instead of using those to connect the networks, you are just
using your service provider to connect through the Internet.?
?Scalability of network: As a company grows, so do its networks and
the distance they need to stretch. Leased-lines may not seem bad at
first, but once the company grows to needing networks in other states
or even countries, the costs become exponentially higher.?
Disadvantages:
?Security issues: VPN requires that whoever is installing the network
knows all of the issues relating to security for public data. VPN
uses protocols and standards beyond simple IP and it is important that
proper security is implemented to prevent data theft.?
?Compatibility issues: Standards are limited with VPN
hardware/software and this can lead to compatibility issues when using
different vendors for different parts/functions of the network?
?Stability issues: When using a VPN to run a WAN, the stability and
speed of the network are not in your complete control since you are
using the Internet and not a physical line to transfer data.?
?Virtual Private Networks (VPN)?
http://www.uwm.edu/People/ajyaeger/vpn.htm
Advantage/Disadvantages of the different VPN Methods:
?The hardware based method consisted of an additional piece of
hardware which takes care of the encryption/decryption method. This is
a benefit since the computers do not have to waste CPU time on the
encryption of the data. Hardware based methods do not provide the
level of configurability available on software methods.?
?A firewall based method has the advantage of any firewall. The
enhanced security the firewall would bring to the system is a plus,
but can also be a hindrance to the system since it will make it harder
to configure. Throughput of this system can also be a concern do to
the extra processing needed by the firewall.?
?A software VPN package is one of the most common VPN packages. This
method requires client software installed on any machine wishes to
remotely access the network. A software package has the ability to
only route necessary data through the VPN. This means that only data
meant for the private network will be sent through the VPN, while data
bound for elsewhere, such as surfing the net, will not be sent to the
private network. A software package is recommended for such
institutions as a school since it is not to difficult and fully
functional for all requirements.?
?Virtual Private Networks?
http://seniord.ee.iastate.edu/ongo07/Subteam/subteam_files/VPN.pdf
Advantages:
?Enables the company to more quickly implement new IP applications?
?Gives the company a more flexible extranet solution?
Disadvantages:
?Most companies feel very uneasy about having their proprietary
information traveling across the internet. Network managers have spent
most of the 90's reading reports of hackers stealing critical
information and getting unauthorized access to company data. The VPN
industry will have to earn the trust of is customers.?
?Another problem is the lack of support of legacy protocols. A lot of
companies have mainframes, which use SNA as a protocol to communicate.
VPNs only use IP as a protocol for communication.?
?Virtual Private Networks: A secure link in an insecure network?
http://www.speech.sir.com/academics/gibbs/students/busn6080-f1-2001-jbh/dinan/Virtual_Private_Networks.htm
Our next link provides a list of technical pros and cons about VPNs.
?VPN: Advantages / Disadvantages?
http://www.geo.umn.edu/dept/computer/wireless_staroffice2/img39.htm
Search terms used:
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Easterangel-ga
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