A VPN creates a secure connection over a public network like the Internet by tunneling link layer protocols. It allows remote users to access private networks. VPNs provide security by using an encrypted connection with another IP address and separating IP traffic. Key functions include authentication, access control, confidentiality, and ensuring data integrity. Common protocols are PPTP, L2TP, IPsec, and SSL/TLS.

1. VPN: Virtual Private
Network
Advanced networks

2. What is VPN?
A Virtual Private Network (VPN) is a network
technology that creates a secure network
connection over a public network such as the
Internet or a private network owned by a service
provider. Large corporations, educational
institutions, and government agencies use VPN
technology to enable remote users to securely
connect to a private network.
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3. What is VPN?
In the virtual network, the link layer protocols are
tunneled through the larger network. VPNs provide
secure communications over the shared public
network, which is the Internet. They are also used for
separating IP traffic over the network using security
features. By using a VPN, users can access a network
through a different IP address other than the one
connecting their computers and the Internet. In virtual
private networking, there is a private network
configured within a shared public network to avail of
the benefits enjoyed by large networks.
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5. Brief Overview of How it
Works
oTwo connections – one is made to the Internet
and the second is made to the VPN.
oDatagrams – contains data, destination and
source information.
oFirewalls – VPNs allow authorized users to pass
through the firewalls.
oProtocols – protocols create the VPN tunnels.
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6. Four Critical Functions
oAuthentication – validates that the data was
sent from the sender.
oAccess control – limiting unauthorized users
from accessing the network.
oConfidentiality – preventing the data to be read
or copied as the data is being transported.
oData Integrity – ensuring that the data has not
been altered
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7. Tunneling
A virtual point-to-point connection made through a
public network. It transports encapsulated datagrams.
Encrypted Inner Datagram
Datagram Header Outer Datagram Data
Area
Original Datagram
Data Encapsulation [From Comer]
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9. Four Protocols used in VPN
1. PPTP -- Point-to-Point Tunneling Protocol
Used to connect a remote client to a private server over
the Internet.
2. L2TP -- Layer 2 Tunneling Protocol
Used to tunnel data communications traffic between two
sites over the Internet.
3. IPsec -- Internet Protocol Security
Used to secure communications over the Internet.
4. SSL and TLS -- Secure Sockets Layer (SSL) and Transport
Layer Security (TLS)
use cryptography to secure communications over the4/3/2015 9

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