Virtual private networks (VPNs) allow remote access to private networks over public telecommunications networks like the Internet. VPNs use encryption, authentication, and tunneling protocols to securely connect remote users to a private network. They provide cost savings over traditional private networks by reducing equipment and maintenance costs while increasing flexibility and scalability. However, VPN performance depends on public networks and proper security deployment is required to mitigate risks.

1. VIRTUAL PRIVATEVIRTUAL PRIVATE
NETWORKS (VPN)NETWORKS (VPN)

2. Traditional ConnectivityTraditional Connectivity

3. What is VPN?What is VPN?
Virtual Private Network is a type of privateVirtual Private Network is a type of private
network that uses public telecommunication,network that uses public telecommunication,
such as the Internet, instead of leased lines tosuch as the Internet, instead of leased lines to
communicate.communicate.
Became popular as more employees worked inBecame popular as more employees worked in
remote locations.remote locations.
Terminologies to understand how VPNs work.Terminologies to understand how VPNs work.

4. Private NetworksPrivate Networks
vs.vs.
Virtual Private NetworksVirtual Private Networks
Employees can access the network (Intranet)Employees can access the network (Intranet)
from remote locations.from remote locations.
Secured networks.Secured networks.
The Internet is used as the backbone for VPNsThe Internet is used as the backbone for VPNs
Saves cost tremendously from reduction ofSaves cost tremendously from reduction of
equipment and maintenance costs.equipment and maintenance costs.
ScalabilityScalability

5. Remote Access Virtual PrivateRemote Access Virtual Private
NetworkNetwork

6. Brief Overview of How it WorksBrief Overview of How it Works
Two connections – one is made to theTwo connections – one is made to the
Internet and the second is made to theInternet and the second is made to the
VPN.VPN.
Datagrams – contains data, destinationDatagrams – contains data, destination
and source information.and source information.
Firewalls – VPNs allow authorized usersFirewalls – VPNs allow authorized users
to pass through the firewalls.to pass through the firewalls.
Protocols – protocols create the VPNProtocols – protocols create the VPN
tunnels.tunnels.

7. Four Critical FunctionsFour Critical Functions
AuthenticationAuthentication – validates that the data was– validates that the data was
sent from the sender.sent from the sender.
Access controlAccess control – limiting unauthorized users– limiting unauthorized users
from accessing the network.from accessing the network.
ConfidentialityConfidentiality – preventing the data to be– preventing the data to be
read or copied as the data is beingread or copied as the data is being
transported.transported.
Data IntegrityData Integrity – ensuring that the data has– ensuring that the data has
not been alterednot been altered

8. EncryptionEncryption
Encryption -- is a method of “scrambling”Encryption -- is a method of “scrambling”
data before transmitting it onto thedata before transmitting it onto the
Internet.Internet.
Public Key Encryption TechniquePublic Key Encryption Technique
Digital signature – for authenticationDigital signature – for authentication

9. TunnelingTunneling
A virtual point-to-point connectionA virtual point-to-point connection
made through a public network. It transportsmade through a public network. It transports
encapsulated datagrams.encapsulated datagrams.
Encrypted Inner Datagram
Datagram Header Outer Datagram Data Area
Original Datagram
Data Encapsulation [From Comer]
Two types of end points:
 Remote Access
 Site-to-Site

10. Four Protocols used in VPNFour Protocols used in VPN
PPTP -- Point-to-Point Tunneling ProtocolPPTP -- Point-to-Point Tunneling Protocol
L2TP -- Layer 2 Tunneling ProtocolL2TP -- Layer 2 Tunneling Protocol
IPsec -- Internet Protocol SecurityIPsec -- Internet Protocol Security
SOCKS – is not used as much as theSOCKS – is not used as much as the
ones aboveones above

11. Types of ImplementationsTypes of Implementations
What does “implementation” mean inWhat does “implementation” mean in
VPNs?VPNs?
3 types3 types
• Intranet – Within an organizationIntranet – Within an organization
• Extranet – Outside an organizationExtranet – Outside an organization
• Remote Access – Employee to BusinessRemote Access – Employee to Business

12. AdvantagesAdvantages
VS.VS.
DisadvantagesDisadvantages

13. Eliminating the need for expensive long-distanceEliminating the need for expensive long-distance
leased linesleased lines
Reducing the long-distance telephone chargesReducing the long-distance telephone charges
for remote access.for remote access.
Transferring the support burden to the serviceTransferring the support burden to the service
providersproviders
Operational costsOperational costs
Advantages: Cost SavingsAdvantages: Cost Savings

14. Flexibility of growthFlexibility of growth
Efficiency with broadband technologyEfficiency with broadband technology
Advantages: ScalabilityAdvantages: Scalability

15. VPNs require an in-depth understanding ofVPNs require an in-depth understanding of
public network security issues and properpublic network security issues and proper
deployment of precautionsdeployment of precautions
Availability and performance depends on factorsAvailability and performance depends on factors
largely outside of their controllargely outside of their control
Immature standardsImmature standards
VPNs need to accommodate protocols otherVPNs need to accommodate protocols other
than IP and existing internal network technologythan IP and existing internal network technology
DisadvantagesDisadvantages

16. ConclusionConclusion
It can be seen that creating and managing aIt can be seen that creating and managing a
VLAN can be quite a complex taskVLAN can be quite a complex task
The LAN administrator needs to have a clearThe LAN administrator needs to have a clear
understanding about how VLANs workunderstanding about how VLANs work
We must know the commands needed inWe must know the commands needed in
order to configure and set up the switches inorder to configure and set up the switches in
his network.his network.

17. www.wikipedia.orgwww.wikipedia.org
www.searchenterprisewan.techtarget.comwww.searchenterprisewan.techtarget.com
www.webopedia.orgwww.webopedia.org
www.technet.microsoft.comwww.technet.microsoft.com
REFERENCESREFERENCES