It is a private network. Use a public network to connect remote sites or users together.
Among its main characteristics are:
1. Encrypted Traffic
2. Remote site is authenticated
3. Support multiple protocols
4. Point to Point Connection
https://securitcrs.files.wordpress.com/2013/04/vpn.gif
But, what is the need to develop VPN?
Share applications and data between offices
Remote workers acces office systems
Reduced leased line cost
Improve communications links with suppliers and customers
Maximize productivity from workers outside the office
Ensure that yoou are secure from outside threats
VPN Tunneling
Is a protocol that allows for the sucure movement of data from one network to another.
The encapsulation process allows for data packets to appear as though they are of a public nature to a public network when they are actually private data packets, allowing them to pass through unnoticed.
Types of VPN
1. Site to Site VPNs
Using ISDN, Frame Relay or ATM
Designed to replace s WAN
2. Remote Access VPNs
Using the internet
Provide remote acces to mobile or branch employees
VPN Protocols
¬ IPsec -- Internet Protocol Security
¬ PPTP -- Point to Point Tunneling Protocol
¬ L2TP -- Layer 2 Tunneling Protocol
¬ SOCKS -- is not used as much as the ones above
>> Security<<
Encryption
Scrambling and unscrambling information
Unscramble - called clear-text
Scrambled information - called cipher-text
Keys
Secret code
8 bits keys = 256 combinations
16 bits keys = 65536 combinations
56 bits keys = 72 057 594 037 927 900 combinations
Authentication
Determine if the sender ir the authorized person and if the data has been redirecting or corrupted
User/system Authentication
Data Authentication
