VPN

1
VPN

• Donald Hughes
• CST 311
• 4-18-02

2
What is a VPN

• Secure connection between two (or many) points
  using internet.

3
Reasons to use a VPN

• Remote offices
• Cost of leased lines
• Scalability

4
Disadvantages of a VPN

• Security
• Dependence on others
• Standards
• Other Protocols

5
How VPN works

• Encryption
• Tunnel
• Decryption

6
Encryption

• Methods
• Shared Key (Symmetric Key Encryption)
• Public Key (Like PGP)
• Algorithms
• MD5, SHA1

7
IPsec

• IPsec Internet Protocol Security Protocol ?
  Can you say repetitive?
• Two modes
• Tunnel (Packet in a Packet)
• Transport (Header left intact)

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More IPSec

• Compliant
• Common Key
• Firewalls
• Devices
• PC ?? Server
• PC ?? Router
• Firewall ?? Router
• Router ?? Router

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AAA (not the car club)

• AAA Server
• Authentication
• Authorization
• Accounting

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Tunneling

• Carrier Protocol
• Encapsulating
• Passenger Protocol

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Analogy Time

• The truck is the carrier protocol, the box is the
  encapsulating protocol and the computer is the
  passenger protocol.

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Encapsulation

• GRE (Generic Routing Encapsulation)
• IPSec (both sides need to have it)
• L2F (Layer 2 Forwarding)
• PPTP (Point to Point Tunneling Protocol)
• L2TP (Layer 2 Tunneling Protocol)

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So what happens on the receiving end?

• Received
• Decoded
• Sent on its way

14
Bibliography

• http//www.howstuffworks.com/vpn.htm
• Special thanks to Coca Cola and R.J. Reynolds
  Tobacco for keeping me awake.