1. CSCI 465 Data Communications and Networks Lecture 26
Martin van Bommel
CSCI 465 Data Communications & Networks

2. Virtual Private Network (VPN)
A set of computers or secure networks interconnected in a secure way through encryption and other security protocols despite using unsecure networks
Unsecure networks contain unauthorized users
Need to prevent eavesdropping
Proprietary solutions insufficient
Little reassurance as to level of security
Limited in choice of network devices
CSCI 465 Data Communications & Networks

3. CSCI 465 Data Communications & Networks
IPSec
Security features part of Internet standards
Authentication and encryption protocols
Applications needing security include
Branch office connectivity
Remote access over Internet
Extranet and intranet connections with partners
E-commerce security
CSCI 465 Data Communications & Networks

4. CSCI 465 Data Communications & Networks
IPSec Functions
Authentication Header
For authentication only
Encapsulating Security Payload (ESP)
Combined authentication/encryption
Key exchange function
Either manual – systems administrator configures keys
Or automated – on-demand key creation
VPNs need both authentication/encryption
CSCI 465 Data Communications & Networks

5. IPSec Tunnel Mode Provides protection to the entire IP Packet
Original IP Packet is encrypted (ESP trailer)
New packet is authenticated (ESP header)
New outer IP header is added
No routers along path will examine inner IP header

6. CSCI 465 Data Communications & Networks
IP Security Scenario
CSCI 465 Data Communications & Networks

7. CSCI 465 Data Communications & Networks
Benefits of IPSec
Provides strong security for external traffic
Resistant to bypass
Operates below transport layer hence transparent to applications
Can be transparent to end users
Can provide security for individual users if needed
CSCI 465 Data Communications & Networks