1. Virtual Private Networks
Ryan Becker
Chris Borowski
May 21, 2004

2. VPN Basics Securely connects any two networks across distances:
Business to Business
Office to Office
Employee to Office
Makes office resources such as file servers, print servers, and local shares accessable as if they were in the cubicle next door

3. VPN Types
Trusted
Secure
Hybrid

4. Trusted VPNs Using dedicated leased line provided by ISP Not encrypted
ISP maintains integrity of the line

5. Secure VPNs Utilizes public lines
Company is responsible for securing their own information through encryption schemes
Encapsulates individual packets with specific protocols

6. Hybrid VPNs Combination of Trusted and Secure VPN
Uses leased lines and encryption mechanism
Holds both parties responsible for maintaining security of transmitted packets

7. VPN Voyage

8. Pros and Cons of VPNs Pros: Cons: Seamless information flow
Allows Telecommuting
Allows easier inter-office/inter-business communication
Provides secure method for ATM/Bank transactions
Cons:
Breaches in security mean severe loss of data integrity and privacy
Securing data is an uphill battle

9. Secure VPN Tunneling
Turns LAN traffic into traffic secured for the open internet:
Carrier protocol - The outside protocol used by the VPN routers to communicate over the internet (PPP)
Encapsulating protocol - The protocol that is wrapped around the original data and protects it from prying eyes (GRE, IPSec, PPTP, L2TP)
Passenger protocol – This is the original protocol in which the packet was being sent across the LAN (IPX, NetBeui, IP)

10. Point to Point Tunneling Protocol (PPTP) Encapsulation
Microsoft Proprietary VPN implementation
Critics say it is easily breakable and flawed
Many still use it because of its easy integration with Microsoft OS’s

11. Layer 2 Tunneling Protocol (L2TP)
Microsoft’s answer to outdated PPTP
Relies on PPP implementing the TCP/IP trafficking
Requires choice of encryption scheme:
SSHv1: vulnerabilities with “man in the middle” attack
SSHv2: vulnerabilities with traffic analysis
Still considerably more secure than PPTP

12. IPSec Most popular VPN implementation Three step security scheme:
Internet Key Exchange (IKE) occurs to transfer encryption/decryption keys to both sides of the VPN.
The Authentication Handler (AH) verifies that both sides of the VPN are who they say they are.
The Encapsulating Security Payload (ESP) will encode the packets using the vendor’s choice of encryption scheme.
Complicated protocol with vague definitions
Therefore many implementations
Administrative overhead

13. AAA Servers Authentication: Who are you?
Authorization: What can you do?
Accounting: What did you do?

14. Security Thoughts from Doug Engelbart
Inventor of the ‘Mouse’
Founder of ARPANET: ‘Second’ Person on the internet
Stressed importance of secure communication protocols
“VPN’s are a great way for companies or individuals to securely communicate.”

15. References Computer Hall of Fame. 16 May 2004
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Englebert, Doug. Personal Interview. May 17, 2004.
Fougere, Jay, “VPNs, 101”
Web Pro News, 15 May, 2004
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Lemos, Robert, “VPN flaw puts internal networks at risk”, September 26, 2002
ZDNet Security News, 16 May, 2004
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Tyson, Jeff, “How Stuff Works”, 15 May 2004
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“VPN Technologies” January 2004
VPN Consortium, 15 May 2004,
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